Iran, the Use of Military Force, and the Constitutional Duty of the Political Branches

The Islamic Republic of Iran presents a sustained and multifaceted national security threat to the United States. That threat is not confined to a single weapon system or a single battlefield. It includes Iran’s nuclear ambitions and missile capabilities, its support for proxy forces across the Middle East, its direct and indirect threats to U.S. personnel and installations, and its willingness to engage in regional escalation to achieve strategic ends. Recent reports of coordinated U.S.–Israeli strikes against Iranian targets, described publicly as major combat operations, and subsequent retaliatory activity underscore both the seriousness of the threat and the gravity of the constitutional moment.

Iran’s strategic posture operates across multiple domains. Its nuclear program and advancing delivery systems create coercive leverage and the risk of rapid escalation. Its missile forces and military-industrial infrastructure enable conventional strikes and strengthen its capacity to arm and sustain aligned proxy groups. Through asymmetric warfare and regional destabilization, Iran applies pressure below the threshold of declared war while preserving plausible deniability. When retaliatory attacks are directed at U.S. bases or allies, the line between gray-zone confrontation and open hostilities narrows dramatically. The threat is therefore cumulative and strategic, not episodic.

At the same time, the constitutional question does not disappear in the face of danger. The President bears solemn responsibility under Article II to protect the nation, defend U.S. forces, and respond to imminent threats. As Commander in Chief, he directs the armed forces and may act decisively to repel attacks and safeguard American lives. The executive power includes authority to respond swiftly in crises where delay could imperil national security. In fast-moving circumstances, the President need not await congressional debate before protecting U.S. personnel from imminent harm.

Yet every use of military force is not constitutionally equivalent to “war.” American constitutional practice has long recognized a distinction between limited uses of force and sustained, large-scale hostilities. Discrete strikes, defensive actions to protect U.S. personnel, rescue operations, or short-duration engagements aimed at neutralizing imminent threats have frequently been justified under the President’s inherent authority. The critical inquiry concerns the anticipated nature, scope, and duration of the operation. When military action becomes prolonged, expansive, and predictably escalatory the constitutional calculus shifts. When it resembles sustained combat rather than limited defense, the constitutional calculus shifts. At that point, Congress’s Article I power to declare war and authorize hostilities moves from peripheral relevance to constitutional necessity.

The governing analytical framework for this separation-of-powers inquiry remains Justice Jackson’s concurrence in Youngstown Sheet & Tube Co. v. Sawyer. Under that framework, presidential authority is strongest when exercised pursuant to express or implied authorization from Congress. If Congress enacts legislation supporting the use of military force against Iran, whether through a tailored Authorization for Use of Military Force (AUMF) or other statutory approval, the President would operate in Youngstown Category 1. In that circumstance, his authority would rest on the combined constitutional powers of both political branches. Judicial deference would be at its apex, and the legitimacy of the operation would be fortified by democratic accountability.

If Congress neither authorizes nor prohibits further action, the President operates in Youngstown’s “zone of twilight.” In this Category 2 setting, authority depends upon the imperatives of events, the gravity of the national interest at stake, and historical practice. Limited defensive operations aimed at protecting U.S. forces or eliminating imminent threats may plausibly reside here. However, as operations expand in intensity or duration, the constitutional footing grows more uncertain. The language of “major combat operations,” particularly when accompanied by regional retaliation and escalation, pushes the analysis closer to the core of Congress’s war powers.

Finally, if Congress enacts binding restrictions, (e.g., through War Powers measures, express statutory prohibitions, or funding limitations), and the President proceeds contrary to that will, executive authority falls to its “lowest ebb” under Youngstown Category 3. In that posture, the President must rely exclusively upon inherent and express constitutional powers that are both assigned to him and exclusive of congressional authority. In the context of sustained hostilities, that is an exceptionally difficult position to maintain.

The current statutory landscape further complicates the analysis. The War Powers Resolution establishes consultation and reporting requirements and provides a procedural framework for congressional involvement, though it does not itself constitute affirmative authorization for war. The 2001 Authorization for Use of Military Force (AUMF) law authorizes force against those responsible for the September 11 attacks and associated forces; its application to broad, state-on-state hostilities with Iran would be legally contested unless tightly connected to covered terrorist entities. The 2002 Iraq AUMF is even more attenuated as a source of authority for major operations against Iran. Meanwhile, executive orders issued under the International Emergency Economic Powers Act and the National Emergencies Act provide tools for economic pressure and sanctions but do not authorize kinetic military action. Thus, if current operations evolve into sustained combat, the most stable legal foundation would not be creative reliance on aging authorizations but fresh and clearly tailored congressional approval.

Congress therefore stands at a constitutional crossroads. It may support the President by enacting a narrowly crafted AUMF defining objectives, geographic scope, reporting requirements, and sunset provisions. It may impose restrictions to prevent mission creep or open-ended engagement. It may exercise the power of the purse to condition or limit expanded hostilities. Or it may seek a constructive middle ground—authorizing defensive force while setting clear boundaries and oversight mechanisms. What Congress may not constitutionally do is abdicate its responsibility altogether. The Framers vested the war power in the legislative branch precisely to ensure deliberation before the nation enters sustained conflict.

From a Christian and constitutional worldview, the moral dimension of war must also be addressed. The Just War tradition, rooted in Augustine and Aquinas and reflected in classical Christian moral reasoning, teaches that war may be justified only when certain criteria are satisfied. These criteria include just cause, legitimate authority, right intention, last resort, proportionality, and a reasonable prospect of success. A sovereign nation may rightly use force to defend its people from actual or imminent aggression. That defensive obligation is consistent both with biblical principles of protecting innocent life and with the Constitution’s design entrusting the political branches with national defense. At the same time, moral clarity requires distinction. The atrocities committed by the Iranian regime against its own people are grievous and condemnable. They may justify sanctions, diplomatic isolation, and moral witness. But internal oppression, however horrific, does not automatically constitute a just cause for the United States to initiate war. By contrast, an imminent and grave threat to American lives, territory, or essential national security interests may satisfy the just-cause requirement for defensive force. The distinction between humanitarian outrage and national self-defense is morally and constitutionally significant. Christian prudence and constitutional fidelity both require that war be waged not for abstract indignation, but for the protection of life, order, and justice within the limits of lawful authority.

The national security threat posed by Iran is real and consequential. The President must have the ability to defend the United States and protect American lives. But the durability and legitimacy of military action, particularly where escalation risks are high, are strengthened, not weakened, when Congress speaks with clarity. Constitutional structure is not an obstacle to national defense; it is its safeguard.

Accordingly, the President should promptly and forthrightly engage Congress as a constitutional partner, seeking authorization calibrated to the threat and bounded to prevent unnecessary escalation. Congress, for its part, should support the President in his solemn duty to defend the nation by providing clear authority, robust oversight, and the resources necessary to deter aggression and protect American lives. When the political branches act together—resolute in defense yet faithful to constitutional design—the nation is strongest, both in security and in liberty.

Bibliography

1. U.S. Constitution, Article I, § 8 (Declare War and related war powers).

   
   

2. U.S. Constitution, Article II, § 2 (Commander in Chief Clause).

   
   

3. War Powers Resolution, Pub. L. 93–148 (1973), codified at 50 U.S.C. §§ 1541–1548 (Chapter 33).

   
   

4. Authorization for Use of Military Force, Pub. L. 107–40 (Sept. 18, 2001) (“2001 AUMF”).

   
   

5. Authorization for Use of Military Force Against Iraq Resolution of 2002, Pub. L. 107–243 (Oct. 16, 2002) (“2002 Iraq AUMF”).

   
   

6. International Emergency Economic Powers Act (IEEPA), 50 U.S.C. §§ 1701 et seq.

   
   

7. National Emergencies Act (NEA), 50 U.S.C. §§ 1601 et seq.

   
   

8. Youngstown Sheet & Tube Co. v. Sawyer, 343 U.S. 579 (1952), especially Justice Jackson’s concurrence.

   
   

9. The Prize Cases, 67 U.S. (2 Black) 635 (1863).

10. U.S. Department of Justice, Office of Legal Counsel, “Authority to Use Military Force in Libya” (Apr. 1, 2011).

11. Lawfare summary/portal linking and contextualizing the OLC Libya opinion (Apr. 7, 2011).

12. The White House, “Addressing Threats to the United States by the Government of Iran,” Presidential Actions (Feb. 6, 2026).

    
    

13. Office of the Director of National Intelligence (ODNI), “Unclassified Assessment Regarding the Regional and Global Terrorism of the Islamic Republic of Iran” (Nov. 2024) (issued pursuant to NDAA reporting requirements).

    
    

14. International Atomic Energy Agency (IAEA), “Verification and monitoring in the Islamic Republic of Iran in light of United Nations Security Council resolution 2231 (2015)” (Report to Board of Governors/UNSC, 2025).

    
    

15. Defense Intelligence Agency (DIA), “Military Power Publications” portal (including “Iran Military Power” and related functional threat reports).

    
    

16. Congressional Research Service (CRS), “Iran’s Ballistic Missile Programs: Background and Context” (June 17, 2025) (as reproduced/linked by USNI News).

17. Iran Watch, “Table of Iran’s Missile Arsenal” (updated Jan. 26, 2026).

    
    

18. Associated Press, report on emergency UN Security Council meeting and reaction to U.S.–Israeli strikes (Feb. 28, 2026).

    
    

19. The Guardian, report describing U.S. and Israel launching strikes and regional upheaval (Feb. 28, 2026).

    
    

20. The Guardian, report on Iranian retaliatory activity and threats toward U.S. bases and Israel (Feb. 28, 2026).

    
    

21. CBS News explainer on Iran’s nuclear program amid U.S. and Israel strikes (Feb. 28, 2026).

22. Washington Post reporting on congressional reactions and war-powers calls (Feb. 28, 2026).

    
    

23. Wall Street Journal reporting on lawmakers’ “illegal/unconstitutional” objections and war-powers initiatives (Feb. 28, 2026).

    
    

24. Yahoo News syndication: “Bipartisan revolt targets Trump’s war powers after massive Iran strikes” (Feb. 28, 2026).

    
    

25. NBC News link you saved (access restricted at time of retrieval): “Democrats force vote to limit Trump Iran strikes…” (RCNA261120).

26. Congress.gov, Constitution Annotated (CONAN): Article I, § 8 and Article II, § 2 materials (war powers; commander in chief).

    
    

27. GovInfo compilations for the 2001 AUMF and the 2002 Iraq AUMF.

28. Thomas Aquinas, Summa Theologiae, II–II, Q. 40 (“Of War”).

    
    

29. Augustine, City of God, Book XIX (and related passages in Augustine’s corpus).

    
    

30. Catechism of the Catholic Church, ¶2309 (“strict conditions for legitimate defense by military force”).

    
    

31. U.S. Conference of Catholic Bishops, “The Harvest of Justice Is Sown in Peace” (1993) (and excerpts on just war tradition).

    
    

32. International Committee of the Red Cross (ICRC), overview on the principle of distinction (Additional Protocols I & II) (1977 framework).

    
    

The author gratefully acknowledges the use of AI-assisted drafting tools (i.e., OpenAI’s ChatGPT) in the preparation of this Issue Brief. All ideas, structural decisions, analysis, and final edits are solely the author’s own, and the author bears full responsibility for the content.