Presidential war power beyond its outer limits

Editor’s note: This post is the second in a three-part series entitled “Is it legal for the U.S. to attack Russia if Russia nukes Ukraine?” by Dakota S. Rudesill, Associate Professor at the Moritz College of Law at The Ohio State University. Image: Framestock/

Part II: Presidential war power beyond its outer limits

This is the second installment of a three-part series addressing the legality under U.S. law of potential U.S. use of force against Russia in response to a Kremlin nuclear attack on Ukraine.

Last summer, Part I explained that the risk of such an atomic atrocity in the course of this unpredictable war is real. Intelligence in fall 2022 that Russia was contemplating use of tactical nuclear weapons prompted officials in the United States and other NATO governments to warn the Kremlin explicitly of a catastrophic” Western response. Anonymous comments to the media by these officials suggested that conventional U.S. military retaliation was one option.

Thankfully, nuclear worries have since declined, but for how long? The stalemate in the war apparent over the past half year is highly unstable. If Russia’s battlefield position again worsens or if Putin’s regime comes under renewed internal threat, then Kremlin nuclear use could be back on the table—and so, too, the prospect of punitive U.S. strikes on Russian targets.   

Today’s post sets out the legal framework for use of force, which reflects the U.S. Constitution’s vision of shared power. As applied, it suggests that a U.S. military strike in response to a Russian nuclear attack on Ukraine, absent an imminent or commenced second Russian attack directed against the United States, U.S. forces, or NATO allies, would not be legal unless authorized by Congress. That is due to the discretionary nature of such a punitive U.S. military attack, and the massive escalation risk. Unilaterally initiating a discretionary war with a peer nuclear power lies beyond the outer edge of presidential war power.

The legal framework for use of force: Shared power

The military is subject to control by both Congress and the president. Article I of the Constitution vests Congress with the powers to “declare War,” create and structure the armed forces, “make Rules” for them, and provide, condition, and terminate spending. Article II of the Constitution gives the president the roles of Commander in Chief of the federal armed forces and chief executive charged with conducting foreign affairs. Article II has been understood since the founding to include the power to “repel sudden attacks.” Longstanding practice reflects also Article II power to initiate other uses of force that do not rise to the level of full war. The ultimate question of war powers is that of control over use of force, which is a zone of shared power. As I have emphasized, this is true even where nuclear weapons are involved.

Under the Youngstown framework, a presidential decision is at its constitutional apex when invested with both Article I and II support through congressional authorization of the president’s order. This is a sunny Youngstown Category 1 situation. When the president acts but Congress is silent, the Commander in Chief’s actions instead fall into Category 2, a “zone of twilight” in which the president must rely only on what Article II allows a president to do on their own. A decision here in the murky constitutional dusk could be legal, or not, depending on the particular presidential act. Where the president acts contrary to “the express or implied will of Congress,” the president’s power is in Category 3 and at its “lowest ebb.” Ambiguity persists regarding the exact contours of expressions of specific Article I and II powers when in conflict at presidential power’s low tide mark. Even so, the overwhelming balance of the evidence from the Founding Era to the 21st century reflects this principle: statutory limitations generally prevail. 

Congress enacted a framework statute in 1973, called the War Powers Resolution (WPR), to govern use of force. Congress’ project was to reassert the Article I branch’s role after decades of expanding presidential discretion.

The WPR is often misunderstood to implicitly authorize the president to wage war until its time limits kick in.

Instead, the WPR is congressional exercise of Article I powers to impose limits and process requirements on the introduction of forces into hostilities grounded on presidential Article II authority and to provide statutory interpretation rules. The WPR requires that the president consult with Congress and submit reports, and that forces be withdrawn within 60-90 days (the “clock”) unless authorized. Under the Youngstown framework, if Congress does not authorize force and the president does not comply with the 60-90 day limit, use of force moves to Category 3’s zone of direct conflict with Congress’ constitutional powers as reflected in the WPR. 

The WPR stipulates that congressional authorization is found only in war declarations and clear statutory statements.  Furthermore, Sec. 8(d) states that the WPR itself does not provide a drop of authority to the president to commit forces to hostilities. One cannot infer a “yes” from such a clear statement of “no.” Also, Sec. 8(a)(1-2) is plain that authorization shall not be inferred from spending laws or treaties. As Michael Glennon has explained, neither NATO decisions on use of force pursuant to articles IV and V of the North Atlantic (NATO) Treaty nor any other treaty sweeps aside the U.S. legal framework. 

The WPR’s normative force has been weakened by a combination of congressional acquiescence, judicial avoidance of war powers questions, and reasonable but problematic and situationally convenient president-favoring executive branch interpretations. Even so, the pattern has mostly been one of presidential compliance. The WPR remains the law of the land.

Returning to the Youngstown framework, in instances where Congress has not spoken, presidential use of force operates in the constitutional twilight of Category 2, not Category 1. In view of the Article I congressional power to “declare War,” most scholars generally agree that a president relying on Article II authority alone could take the country into a full “War” if, and only if, acting in self-defense. The Department of Justice’s Office of Legal Counsel (OLC) appears to concur, while protecting its presidential principal with ambiguous hedging language, as one might expect: “a planned military engagement that constitutes a ‘war’…may require prior congressional authorization.” In short, there is good reason to conclude that the president cannot start an optional full war on their own.

The framework, applied

There are four circumstances in which the president can order the military into hostilities. Applied to our scenario, here is the bottom line: Absent congressional authorization, and absent initiated or clear evidence of an imminent Russian attack on the United States, its forces, or NATO allies, the legal case is weak for a U.S. punitive attack on Russia for nuking Ukraine. This analysis considers military kinetic force: blowing things up with physical weapons.

A.  Congress has not authorized force

There is no war declaration, no authorization for the use of military force (AUMF), and (as explained above) no part of the WPR authorizes kinetic force against Russian targets. 

Statutory silence puts a U.S. punitive strike into the constitutional zone of twilight, Youngstown Category 2. To be legal, the strike would need authority in Article II alone. Based on our constitutional history, there are, in theory, three different ways Article II authority could operate. Here, however, they provide highly questionable to zero authority.

B.  No “repel sudden attacks” presidential authority

Since the founding, the president has been understood to possess authority to order federal forces into action to repel initiated attacks against U.S. territory, forces, or persons.

Though monstrous, a nuclear attack by a second country on a third country is not an armed attack on the United States. Except for a handful of Marines and other uniformed personnel protecting or performing other diplomatic functions at the U.S. Embassy in Kyiv, the United States does not have military forces in Ukraine that would be harmed by or targeted in a nuclear strike. A Russian armed attack on a NATO ally might raise an inference that Article II “repel sudden attacks” authority is operative because of the importance of NATO to U.S. national security for more than three quarters of a century, but Ukraine is not in NATO.

C.  No anticipatory self-defense presidential authority 

The idea is contested, but an anticipatory self-defense prerogative—that is, the power not to wait for the enemy’s imminent first blow to land—logically flows from the Article II “repel sudden attacks” power. In view of Congress’ Article I power to “declare War,” that theory requires a good faith presidential judgement of true imminence of foreign attack and necessity of striking first: there is no real possibility of avoiding combat, there is only a fleeting opportunity to preempt and thereby block or mitigate the incoming foreign assault, and there is no time to go to Congress. 

Russian escalation against Ukraine does not necessarily mean that a second significant attack on the United States, its forces, or allies is impending. Putin could reasonably be deterred from war with NATO but not deterred from a nuclear attack on Ukraine.

The strongest argument for an Article II preemptive or anticipatory self-defense power goes like this: Russia has global-range nuclear and conventional forces that can be launched in minutes. Russia also has a large army in Ukraine in range of U.S. forces on the territory of NATO allies and has made repeated verbal threats against NATO. Russia demonstrated poor judgment and risk-taking in initiating full-scale war against Ukraine. In this circumstance, a Russian nuclear attack on Ukraine could suggest Russian willingness to make dangerous moves. The president therefore needs the authority to decide when to strike first—to deter Russian aggression, to destroy Kremlin military capabilities, or both. Judgement about generalized long-term threats, this argument would go, lies with the president. The president may have to act quickly in our age of hypersonic missiles and global-range nuclear forces. A lawyer would cite The Prize Cases, in which the Supreme Court upheld President Lincoln’s use of force against the slaver confederate insurrectionists during the Civil War, because it is up to the president to assess the threat and act.

This argument fails for two reasons. First, The Prize Cases, although including ringing dicta, upheld presidential use of force in a fairly simple “repel sudden attacks” circumstance: the South had struck first.  This was not a preemption case. Second, neither the vision of the Framers nor the structure of the Constitution grants the president the power to incant the magic words “Article II” and “I predict an adversary attack at some unknown time” and then legally order the military to attack anyone, anywhere, at any time, generating war of any scale of the president’s choosing, subject only to a funding cut-off, re-election defeat, impeachment and removal, or (today) removal by the cabinet for incapacity under the 25th Amendment. Whatever power that would allow for a far-sighted president to pre-empt in good faith a temporally distant attack would impermissibly carry, too, a presidential power of war-at-whim.  

Our constitutional vision—reflected in the Constitution’s text, structure, purpose, original understanding, interpretation, and the practice “gloss” of history—commands that the president make the highest quality good faith determination that a foreign attack is truly imminent and that there is simply not time for Congress to act. (And Congress can act quickly—it declared war the day after Japan bombed Pearl Harbor).  Presidential fidelity to the Constitution’s vision of shared power is especially imperative when a discretionary use of force could foreseeably escalate to global conventional war and then nuclear war.

D.  Iffy “national interests” presidential authority

Justice Department OLC opinions and longstanding practice recognize presidential authority to use force at a level less intense than “War” without an imminent self-defense rationale and without congressional authorization (so, in Youngstown’s murky Category 2), in order to protect important national interests. These include promotion of international peace and security, deterrence of use of weapons of mass destruction, and protection of the credibility of international organizations.

Such rationales have undergirded OLC recognition of the legality of presidential uses of force in Somalia, Haiti, Syria, Bosnia, Kosovo, and Libya. Under OLC’s criteria, those U.S. military actions were not intense or perilous enough to implicate the Declare War Clause and require congressional authorization. OLC typically looks at factors including the scope and duration of the operation, the risk to U.S. personnel, and the risk of escalation.

By each of these metrics, a U.S. punitive strike on Russian forces would be completely different.  None of the countries just mentioned had any real power to attack the United States. With Russia, there is immense risk of escalation to a massive, lengthy, costly global war. Indeed, Putin, at a desperate moment, may see U.S. entry into the war as a gift and further escalation as a good gamble. An attack by the United States could help him domestically and geopolitically change a losing game. No one knows if a NATO/Russia war could be controlled. 

One may reasonably wonder if use of force in Korea without congressional authorization, our national interests in NATO and the UN, or the transnational effects of nuclear weapons may provide support for an “international peace and security” argument for unilateral presidential war power in our scenario. These are not unreasonable considerations, and I explore them in the longer version of this analysis forthcoming in The Ohio State Law Journal. Suffice for now to note that these are highly questionable legal theories when applied here. 

In short, the existential danger, and the risk of unilateral presidential action denying Congress the opportunity to exercise its constitutional powers regarding a discretionary war, are powerful considerations that out-balance any important national interests theory of Article II power to sink the Black Sea Fleet and then wage whatever game-changing Third World War to which Putin might thereafter decide to escalate in response.

No president can constitutionally take the United States into a discretionary and potentially humanity-ending full “War” in the constitutional sense on their own. But that does not mean that the war powers framework prevents the United States from making Russia pay a high price for a nuclear attack on Ukraine. Far from it. The concluding Part III of this series outlines alternatives with considerable potential to deter and punish such an atomic atrocity.

Dakota S. Rudesill is an Associate Professor of Law at the Moritz College of Law at The Ohio State University.  You can find his scholarship here at SSRN and follow him on Twitter/X.

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