Introduction
The framers of the United States Constitution intentionally divided war-making authority to prevent its concentration in one branch. Article I gives Congress the power to declare war, raise armies, and control military funding, while Article II designates the President as commander-in-chief once conflict begins (U.S. Const. Art. I, sec. 8; art. II, sec. 2). This system was designed so that decisions about war would require deliberation across branches rather than quick action by a single actor. Over time, that system has changed in practice, and this shift matters because war powers shape conflicts through three main mechanisms: permission, visibility, and enforcement. Broad authorizations give presidents permission to expand or continue military action without returning to Congress for new approval. Contractor use and separate funding structures can make the full scale of conflict less visible to Congress and the public. Weak enforcement means that formal limits, such as War Powers reporting requirements or funding controls, may exist on paper but fail to meaningfully constrain military action. Since the War Powers Resolution was passed in 1973, presidents have increasingly relied on broad statutory delegations, flexible interpretations of executive authority, and existing authorizations to initiate or sustain military operations without clear prior congressional approval (Bridgeman, 2020; Ingber, 2024). Looking at this shift through a governmental lens changes the focus of the analysis. Instead of asking whether a specific war was justified or which leader made the better decision, the focus becomes how the structure of authority itself relates to outcomes. Viewed through a global justice and human rights lens, the allocation of war-making power is not merely a constitutional question about which branch may authorize force; it is also a question of who bears the human costs when institutional safeguards fail, particularly civilians whose rights, security, livelihoods, and communities may be profoundly affected by decisions over which they have little or no democratic influence. This paper examines how legal frameworks, authorization structures, funding systems, private military contractor usage, and enforcement tools connect to observable indicators like escalation, alliance behavior, humanitarian impact, and conflict duration. The goal is not to argue that one arrangement is always better. The stronger claim is that Congress’s policy design changes the incentives and constraints around how we go to war. When Congress authorizes force with broad authorization, it typically fails to include sunset clauses or continues funding without a limit, making it harder to stop the war in the future, or in other words, causing prolonged engagement. When oversight tools are hyper-specific, enforced over a long time, and connected to funding, they put pressure for accountability. By looking across these cases, the paper shows how the structure of war-making authority connects not only to how conflicts develop and endure, but also to who ultimately bears their political, economic, and humanitarian consequences (Howell & Pevehouse, 2007; Nzelibe, 2005). At the same time, wars themselves are rarely caused by a single event. While conflicts are often triggered by immediate crises, deeper causes include competition over resources such as oil, security concerns, ideological differences, and the pursuit of influence (Fearon, 1995; Klare, 2001). For example, access to energy resources has shaped strategic decisions in the Middle East, while ideological rivalry influenced conflicts like Vietnam (Walt, 1987). These patterns are not limited to a single conflict. Cases such as Korea, Vietnam, and Ukraine show similar dynamics, where initial triggers led to broader and longer engagements shaped by institutional decisions and international involvement (Cumings, 2010; Logevall, 2012; Mearsheimer, 2001).
Methods
This study uses comparative case analysis to identify recurring patterns across conflicts. While this approach is useful for examining similarities and differences across cases, it cannot establish causation in the same manner as a controlled experiment. Wars are shaped by numerous factors beyond institutional structure, including enemy behavior, geography, military strategy, alliance politics, domestic political conditions, and local circumstances. Accordingly, this paper treats institutional design as an important shaping factor rather than the sole cause of escalation, conflict duration, or humanitarian harm. The comparison is intended to identify how similar institutional patterns emerge across different cases, rather than to suggest that any single variable directly determines conflict outcomes.
A governmental lens focuses on how rules, institutional structures, and divisions of authority shape political and military outcomes. Rather than centering individual leaders or isolated conflicts, this approach examines how authority is organized and how decisions are made within institutional systems (Dahl, 1989; Feaver, 2003). Applied to U.S. military engagement, this involves examining the Constitution, the War Powers Resolution, Authorizations for Use of Military Force (AUMFs), the National Defense Authorization Act, appropriations, reporting requirements, and congressional oversight as interconnected parts of a broader system (Glennon, 2014; Goldsmith, 2012).
This lens also emphasizes enforcement—that is, whether formal rules meaningfully constrain or shape decision-making in practice. Funding restrictions, reporting requirements, sunset clauses, repeal authority, and oversight of private military contractors can all influence the degree of control exercised by each branch of government. When used consistently, these mechanisms can shape the development and continuation of military engagements. When they are weak, inconsistently applied, or absent, the institutional system may appear balanced formally while operating quite differently in practice (Ingber, 2024; Waxman, 2024).
At the same time, this framework does not assume that congressional involvement necessarily limits conflict. Congress may itself authorize broad military authority, as demonstrated by the 2001 AUMF. The purpose, therefore, is not to presume particular outcomes but to examine how different structures of authority correspond with patterns observed across conflicts. This approach also helps explain how underlying causes of conflict translate into governmental action. Resource competition may create pressure for involvement, but whether that pressure results in military action depends partly on institutional structures. Security threats may encourage rapid responses, while ideological conflicts can contribute to prolonged engagement (Fearon, 1995). The Vietnam War, for example, illustrates how expanded executive authority following the Gulf of Tonkin Resolution facilitated prolonged military involvement, while the Korean War demonstrates how international alliances can expand a conflict beyond its original scope (Logevall, 2012; Cumings, 2010).
The selected cases are Afghanistan, Iraq, Vietnam, Korea, and Ukraine. Afghanistan is included because it was shaped by the 2001 AUMF, one of the broadest and longest-lasting authorizations in modern U.S. history. The conflict also involved NATO participation, prolonged counterterrorism operations, extensive contractor use, and substantial financial and humanitarian costs. Iraq is included because it was authorized through the 2002 Iraq AUMF, which was more specific than the 2001 authorization but remained broad enough to support a major military intervention. Iraq also demonstrates how congressional authorization can provide domestic legal legitimacy while international support remains contested.
Vietnam is included because the Gulf of Tonkin Resolution provides an earlier example of broad congressional delegation that facilitated escalation. Korea is included because it demonstrates how U.S. military action can occur without a formal declaration of war and how international institutions and alliance commitments can expand the scale of conflict. Ukraine differs from the other cases because the United States has not engaged in the conflict as a direct combatant. Nevertheless, it provides an important case for examining how military assistance, alliance coordination, and congressional funding can shape conflict dynamics without direct U.S. combat deployment.
Together, these cases permit comparison across different historical periods, legal frameworks, and degrees of direct U.S. involvement. They are not identical conflicts and are not treated as such. Instead, the comparison focuses on common analytical dimensions: the scope of authorization, congressional participation, oversight mechanisms, alliance involvement, conflict expansion, contractor use, funding, and humanitarian impact.
The analysis compares each case according to four primary criteria. First, it examines authorization structure, including whether Congress formally authorized force, the breadth of that authorization, whether geographic or temporal limitations were imposed, and whether a sunset clause was included. Second, it considers oversight and enforcement mechanisms, including War Powers reporting, funding restrictions, repeal efforts, congressional hearings, and contractor oversight. Third, it examines conflict development, including escalation, geographic expansion, duration, and the involvement of contractors or partner forces. Fourth, it considers external and humanitarian outcomes, including alliance participation, civilian harm, military deaths, displacement, and fiscal costs. Because these outcomes are influenced by numerous factors beyond U.S. institutional arrangements, they are used to identify comparative patterns rather than to establish simple or direct causal relationships. Including humanitarian outcomes also allows the analysis to consider a broader global justice question: whether the institutional structures governing decisions to use and sustain force provide meaningful accountability for harms experienced by civilian populations beyond U.S. borders.
Conflicts frequently emerge from overlapping causes rather than a single factor. Resource competition is one important consideration. Oil and energy access have influenced strategic decision-making, particularly in regions where control over resources affects economic stability and geopolitical influence (Klare, 2001). Security concerns are another major factor, as states may act in response to perceived threats or in an effort to prevent future threats (Fearon, 1995). These motivations often intersect. In Vietnam, ideological concerns surrounding communism overlapped with security considerations, while in Ukraine regional security concerns intersect with broader geopolitical competition (Logevall, 2012; Mearsheimer, 2001). In Iran and Venezuela, economic pressure and strategic influence play a more prominent role, illustrating how conflict and competition can take forms other than direct warfare (Brands, 2018). Similar security dynamics can be observed in Afghanistan following the September 11 attacks and in Korea, where intervention was framed as necessary to preserve regional stability (Cumings, 2010). Ideology likewise remains significant. During the Cold War, conflicts such as Vietnam were shaped by competing political systems and efforts to contain communism (Logevall, 2012). More broadly, considerations of influence and power continue to shape state behavior. In Ukraine, the conflict reflects wider competition among major powers (Mearsheimer, 2001), while tensions involving Iran and Venezuela have relied more heavily on sanctions and strategic positioning than on full-scale war (Brands, 2018).
The War Powers Resolution of 1973 was designed to structure the relationship between Congress and the President when U.S. forces are introduced into hostilities or situations in which hostilities are likely (Congressional Research Service, 2008). It requires consultation before deployment, reporting within 48 hours, and withdrawal after 60 days unless Congress authorizes continued military operations.
In practice, however, these enforcement mechanisms have rarely been used in a consequential manner. From 1975 through 2017, presidents submitted 168 War Powers reports, yet only one triggered the 60-day withdrawal provision (Congressional Research Service, 2023). Executive branch legal offices have repeatedly interpreted military operations in ways that avoid triggering this statutory timeline, raising questions about the extent to which the Resolution meaningfully constrains presidential action (Ingber, 2024). The 2011 Libya operation illustrates this pattern. Although the administration reported its actions to Congress, it maintained that U.S. involvement did not constitute “hostilities” under the law and therefore did not activate the 60-day requirement. Members of Congress challenged this interpretation, but no formal enforcement action followed (Congressional Research Service, 2023).
The 2001 Authorization for Use of Military Force passed with overwhelming congressional support—98–0 in the Senate and 420–1 in the House. It authorized the President to use force against those responsible for the September 11 attacks and those who supported them (Weed, 2015). Its language was intentionally broad, containing no geographic limitations, sunset clause, or clearly defined endpoint. As a result, it has been invoked to justify military operations in more than a dozen countries over more than two decades (Torreon & Davis-Castro, 2023). This demonstrates how broadly framed authorization can operate less as a targeted decision and more as continuing permission for military action. Without mechanisms such as sunset provisions or geographic restrictions, the authorization extended well beyond its original context (Nzelibe, 2005; Weed, 2015).
The 2002 Iraq AUMF received comparatively less congressional support, passing 296–133 in the House and 77–23 in the Senate (Congressional Research Service, 2023). Unlike the 2001 AUMF, it was tied to specific findings concerning Iraq and contained reporting requirements that provided some degree of continuing accountability. The FY2026 National Defense Authorization Act later repealed both the 1991 and 2002 Iraq-related AUMFs, demonstrating Congress’s ability to withdraw authorization after the fact. This provides an example of retrospective enforcement, in which congressional action occurs after a conflict and its institutional framework have already developed (GovInfo, 2025). Comparable patterns appear in earlier conflicts. The Gulf of Tonkin Resolution functioned as a broad authorization that facilitated escalation in Vietnam, while the absence of a formal declaration of war in Korea demonstrates how executive decision-making and international commitments can shape military involvement outside traditional congressional processes (Logevall, 2012; Cumings, 2010).
Private military contractors (PMCs) constitute another important component of contemporary military engagement. Their use allows executive policy to be implemented through mechanisms that may be less visible to Congress because contractor oversight differs from the oversight applied to uniformed military personnel (Carson, 2018; Singer, 2003). In Iraq and Afghanistan, contractor numbers at times matched or exceeded the number of uniformed personnel. At peak levels, the Department of Defense employed more than 150,000 contractors in these conflicts (Thompson, 2007).
Because contractors are categorized differently within reporting systems, their involvement can make the overall scale of military engagement less apparent. From a governmental perspective, this creates a potential gap between formal oversight mechanisms and operational realities. War Powers reporting generally emphasizes troop deployments, while congressional oversight is often structured around those figures. Contractor participation does not always fit neatly within these frameworks and may therefore be incompletely captured (Goldsmith, 2012). Contractors are also managed through executive procurement systems, providing the executive branch with greater flexibility to expand or sustain operations without obtaining new congressional authorization. This creates an additional institutional pathway through which military activity can continue partly outside traditional oversight mechanisms (Ingber, 2024).
Ultimately, enforcement determines whether institutional rules meaningfully shape outcomes. Some mechanisms operate prospectively, before or during initial decisions, while others function retrospectively after military action has begun (Howell & Pevehouse, 2007). Prospective mechanisms include requirements for prior congressional authorization and provisions such as sunset clauses. These mechanisms encourage deliberation and establish institutional checkpoints before or during military engagement. The differing vote margins for the 2001 and 2002 AUMFs demonstrate how congressional agreement can vary substantially and can signal different levels of political support (Congressional Research Service, 2023).
Sunset clauses are particularly significant because they require Congress to reconsider earlier decisions. The absence of such a provision in the 2001 AUMF allowed the authorization to remain in force across multiple presidential administrations (Weed, 2015). Retrospective mechanisms include reporting requirements, congressional oversight, and repeal authority. These measures can establish accountability after military action begins, although they do not necessarily prevent escalation (Waxman, 2024). Funding remains among Congress’s most powerful institutional tools (Howell & Moe, 2016). In principle, Congress can constrain or terminate military operations by restricting appropriations. In practice, however, funding mechanisms can also sustain conflicts rather than constrain them. The Overseas Contingency Operations budget, for example, established a separate funding stream for war-related expenditures, reducing some forms of scrutiny and making it easier to sustain military operations over extended periods (Congressional Budget Office, 2018).
Results
Alliance Behaviors
The way military action is authorized domestically can affect how allies respond internationally. In Afghanistan, the near-unanimous passage of the 2001 AUMF was followed by NATO invoking Article 5 for the first time. More than 50 countries contributed forces to the mission (NATO, 2022). This suggests that strong domestic agreement can signal reliability and encourage broad alliance participation. In Iraq, the 2002 AUMF passed with less consensus, and the coalition that formed was smaller and less unified. Some major allies chose not to participate, reflecting a different international response (Jentleson, 2014). In Korea, United Nations involvement transformed a regional conflict into a multinational effort, while in Ukraine, external military and economic support from multiple countries has played a key role in sustaining the conflict (Cumings, 2010; Mearsheimer, 2001). At the same time, shared authority can create uncertainty for allies. If decisions depend on multiple branches, partners may question how quickly the United States can act or how stable its commitments are over time (Hulme & Waxman, 2023).
Escalation Patterns
Broad authorizations can allow conflicts to expand over time. The 2001 AUMF, with no geographic limits, allowed operations to spread across multiple regions (Bridgeman, 2020). In Libya, legal interpretation was used to avoid War Powers limits, showing how executive framing can shape escalation (Ingber, 2024). Because these examples are still developing or hypothetical as of early 2026, they should be treated as illustrative of a possible pattern rather than as established evidence equal to fully documented historical cases.This reflects a broader pattern where executive action builds on existing frameworks rather than seeking new approval (Lee, 2026; Mann, 2025). Across cases such as Vietnam, Afghanistan, and Ukraine, escalation often occurs in stages, with initial limited objectives expanding into broader engagements as additional actors and interests become involved (Logevall, 2012; Bridgeman, 2020; Mearsheimer, 2001).
Analyzing Conflicts
Conflict duration is closely connected to humanitarian outcomes. Longer conflicts often lead to greater cumulative harm. In Afghanistan, UN data recorded 5,183 civilian casualties in just the first half of 2021 (UNAMA, 2021). Over time, these effects add up, especially in conflicts that last for decades. These patterns connect to how authority is structured. Open-ended authorizations without clear limits allow conflicts to continue longer, which can increase total harm even if yearly casualty rates change. In Iraq, differences in coalition structure also mattered. NATO’s more integrated command in Afghanistan created stronger oversight systems than the more loosely organized Coalition of the Willing in Iraq (Kreps, 2011; Lake, 2009). Research suggests that more coordinated coalitions can create more accountability, which may reduce civilian harm (Downes, 2008). Fiscal data also reflects the conflict scale. The Department of Defense reports approximately $849.8 billion spent in Afghanistan and $787.5 billion in Iraq and Syria between 2001 and 2021 (Department of Defense, 2022). The growth of the Overseas Contingency Operations budget shows how funding structures can support long-term conflict by reducing oversight pressure (Congressional Budget Office, 2018). These patterns are consistent across conflicts. Vietnam and Korea both show that even when intensity decreases, conflicts can persist for extended periods, while more recent cases like Ukraine demonstrate how sustained external involvement can prolong conflict even without direct escalation by a single actor (Logevall, 2012; Cumings, 2010; Mearsheimer, 2001).
Comparative Institutional Analysis
The following table summarizes yearly conflict deaths across selected wars, showing how different causes of war correspond to patterns of escalation, peak intensity, and prolonged engagement over time.
Discussion
Looking at these cases through a governmental lens, a few clear patterns start to show up: First, how broad an authorization is seems to connect to how long and how far conflicts expand. The 2001 AUMF was written very broadly, with no sunset clause or clear limits, and it has been used for over two decades across multiple regions (Bridgeman, 2020; Weed, 2015). The 2002 Iraq AUMF was also broad, but because it was tied more specifically to Iraq, it was easier to repeal later. This lines up with research on delegation, which shows that when Congress gives authority without clear limits or accountability mechanisms, that authority is more likely to expand over time (Howell & Moe, 2016; Nzelibe, 2005).
Second, coalition structure seems to connect to how much agreement there is at home. The 2001 AUMF passed almost unanimously and was followed by NATO involvement and support from the United Nations, creating one of the largest coalitions in recent history. The 2002 Iraq authorization had more disagreement and no UN backing, and the coalition that formed was smaller and less unified. This fits with alliance theory, which suggests that when there is strong domestic agreement, allies are more likely to view commitments as reliable (Kreps, 2011; Walt, 1987).
Third, private military contractors create a gap in oversight. War Powers rules and reporting requirements focus on troops, not contractors, even when contractors are doing similar work. Because of this, the full scale of U.S. involvement in conflicts like Iraq and Afghanistan is not always captured in official oversight systems (Carson, 2018; Glennon, 2014). That means looking only at troop data or authorization votes can miss part of what is actually happening.
Fourth, enforcement mechanisms are not used consistently. The War Powers Resolution technically includes a 60-day limit, but it has rarely been enforced. Reporting requirements in the WPR are sometimes followed and sometimes not. Oversight of contractors is incomplete. These patterns suggest that it is not just the existence of rules that matters, but whether they are actually applied in practice (Ingber, 2024; Waxman, 2024).
Finally, outside data on costs and humanitarian impact lines up with these patterns. The long duration of conflicts like Afghanistan and Iraq, the high financial costs, and the levels of civilian harm and displacement all connect to systems where authorizations were broad and oversight was limited. At the same time, cases with more structured oversight, such as operations with regular reporting requirements, show different accountability patterns even when costs remain high (Department of Defense, 2022; UNHCR, n.d.; UNAMA, 2021). From a global justice perspective, this relationship is particularly important because the consequences of institutional decisions are not distributed equally. Decisions about authorization, funding, and continuation are made primarily within U.S. political institutions, while many of the most severe consequences—including civilian casualties, displacement, insecurity, and loss of livelihood—are experienced by populations outside those institutions and with little ability to influence them.
Policy Implications
These findings suggest several lessons for war powers reform. First, future authorizations should include sunset clauses. A sunset clause forces Congress to revisit the conflict after a set period and decide whether the mission still fits its original purpose. This would not prevent all escalation, but it would make long-term continuation require renewed democratic approval. Second, authorizations should include geographic and enemy-specific limits. If Congress authorizes force against a specific group in a specific region, later expansion should require a new vote. This would reduce the ability of administrations to stretch old authorizations into new conflicts.
Third, War Powers reporting should include clearer definitions of hostilities and military involvement. If the executive branch can define “hostilities” narrowly, the 60-day clock becomes weak. A clearer definition would reduce the ability to avoid the statute through legal interpretation. Fourth, contractor reporting should be strengthened. Congress should require regular public reporting on contractor numbers, roles, costs, and locations when contractors support military operations. This would make the actual scale of involvement more visible.
Finally, funding should be tied more directly to authorization. If a conflict continues beyond its original legal basis, Congress should have to affirmatively approve continued funding for that mission. This would make appropriations a real oversight tool rather than a routine continuation mechanism.
Limitations
There are several limits to this analysis.
First, the definition of “hostilities” under the War Powers Resolution is not clear and is applied differently in different cases. This affects which operations are officially reported and which are not, which can change what data is available (Congressional Research Service, 2008; Ingber, 2024). Second, data on private military contractors is incomplete. Reporting requirements have not been applied consistently, so contractor activity and costs are only partially captured in public sources (Torreon & Davis-Castro, 2023). Third, outcomes like coalition size, civilian harm, and displacement are influenced by many factors beyond the U.S. government structure. These include the actions of other countries, regional politics, and conditions within the countries where conflicts occur. Because of this, the patterns identified here show relationships, not direct cause-and-effect (Fearon, 1995). Fourth, the selected cases differ significantly in time period, legal context, and type of involvement. Afghanistan and Iraq involved direct U.S. military operations, while Ukraine involved U.S. support without direct U.S. combat deployment. These differences limit direct comparison, but they also help show how war powers operate across different forms of engagement. And lastly, recent or developing examples should be treated cautiously. Claims about future or ongoing conflicts may change as new evidence emerges. For this reason, this revised manuscript uses recent examples only to illustrate possible patterns of authority reuse, not as central evidence for the paper’s conclusions.
Conclusion
Taken together, cases such as Afghanistan, Vietnam, Korea, and Ukraine show that while the causes of war differ, the structure of authority and involvement consistently shapes how conflicts expand, persist, and eventually decline (Biddle, 2004; Logevall, 2012; Cumings, 2010; Mearsheimer, 2001). Looking at U.S. war powers through a governmental lens shows a system where authority is shared on paper but works differently in practice. Broad authorizations without clear limits tend to line up with longer and more expanded conflicts. Coalition size and structure vary depending on how much agreement exists at home and whether there is international backing. The use of private military contractors creates gaps in oversight, and funding systems often support conflicts rather than limit them. The strongest conclusion is not that Congress always prevents war or that presidents always expand it. The evidence does not support such a simple claim. Congress can authorize broad conflicts, and presidents can sometimes act quickly in ways that respond to real threats. The more precise lesson is that institutional design affects how easy it is for conflicts to grow and how difficult it is to end them. When authorizations lack sunset clauses, geographic limits, and clear reporting requirements, military engagement becomes easier to sustain across time and administrations. When oversight tools are specific and tied to funding, Congress has a stronger ability to monitor and limit conflict. This matters for future war powers reform because the most important changes are not only theoretical debates about which branch should have more power. The evidence points to concrete design choices. Sunset clauses would force Congress to revisit long-running missions. Geographic and enemy-specific limits would make it harder to stretch old authorizations into new conflicts. Clearer definitions of hostilities would reduce executive avoidance of the War Powers Resolution, while stronger contractor reporting would make the full scale of military involvement more visible. These reforms would not eliminate war, but they would make continued military engagement harder to hide, easier to debate, and more accountable to democratic institutions. Such accountability also has implications beyond American constitutional governance: stronger institutional constraints may provide greater scrutiny of the human consequences imposed on populations who bear the costs of military action but have little voice in the political processes that authorize or sustain it.
Future research should move in two directions. First, scholars should study whether sunset clauses, repeal provisions, and funding restrictions actually change presidential behavior once they are included in authorizations. Second, future work should examine newer forms of military involvement, including drone campaigns, cyber operations, security assistance, special operations forces, and contractor-led missions. This will give a better understanding of whether the United States has a system that can authorize, monitor, and limit force before conflicts expand beyond their original purpose.