The Presidency and the Power to Make War: When One Person Decides

By Cliff Potts, CSO, and Editor-in-Chief of WPS News

Baybay City, Leyte, Philippines — September 29, 2026

The Constitution does not give the president of the United States an unrestricted power to take the nation to war.

It gives Congress the power to declare war.

It gives Congress authority to raise and support armies, provide and maintain a navy, regulate the armed forces, and appropriate the money necessary to sustain military operations (U.S. Const. art. I, § 8).

The president, meanwhile, is commander in chief of the armed forces (U.S. Const. art. II, § 2).

For more than two centuries, presidents and Congresses have argued about where one authority ends and the other begins.

Donald Trump’s second presidency has brought that argument back with extraordinary force.

In June 2025, Trump ordered U.S. military strikes against Iranian nuclear facilities without first obtaining specific authorization from Congress. The administration defended the operation as a lawful exercise of presidential authority. Critics in Congress argued that Trump had usurped a power constitutionally reserved to the legislature (The White House, 2025a; Congressional Research Service [CRS], 2025a).

The disagreement became so serious that Representative Al Green introduced an article of impeachment specifically accusing Trump of violating Congress’s constitutional war power (U.S. House of Representatives, 2025a).

That does not establish that Trump committed an impeachable offense.

But unlike some theoretical arguments surrounding a possible third impeachment, this one already exists in black and white.

A member of Congress has formally alleged that Trump’s use of military force constitutes a high crime and misdemeanor.

The question is whether the constitutional argument holds.

The Constitution Divided the War Powers Deliberately

The Framers had experience with kings.

They understood the danger of allowing a single executive to decide when a nation would enter war.

The Constitution therefore divided military authority.

Congress received the power to declare war and control military funding. The president became commander in chief, providing the executive leadership necessary to direct military operations (U.S. Const. art. I, § 8; art. II, § 2).

James Madison considered this division essential. He argued that the Constitution had deliberately transferred the power to initiate war away from the executive because executives historically were particularly inclined toward war (Madison, 1793/1906).

Alexander Hamilton—often associated with a strong executive—also distinguished the American president’s military authority from that of the British king. In Federalist No. 69, Hamilton emphasized that the president’s commander-in-chief authority was narrower than the British monarch’s authority to declare war and raise armies (Hamilton, 1788/1961).

The basic design was therefore intentional.

The president commands forces.

Congress decides whether the nation will legally commit itself to war.

At least, that was the theory.

Two Centuries Changed the Practice

American history complicated the constitutional arrangement almost immediately.

Presidents have repeatedly deployed military force without formal declarations of war.

Korea.

Vietnam.

Grenada.

Panama.

Kosovo.

Libya.

Operations in Iraq and Syria.

Numerous smaller interventions, strikes, raids, deployments, and covert operations.

Congress has sometimes authorized force without formally declaring war. At other times presidents have relied upon their Article II authority as commander in chief and chief executive.

The result is a constitutional gray area considerably larger than the text of Article I might initially suggest.

Modern presidents of both parties have asserted authority to conduct limited military operations without advance congressional authorization when they conclude that important national interests are involved and when the anticipated scope, nature, and duration of hostilities do not rise to the constitutional meaning of “war” requiring congressional authorization (CRS, 2025a).

Trump did not invent that theory.

Democratic and Republican administrations have used versions of it for decades.

That fact matters when evaluating whether his actions are impeachable.

Congress Tried to Reassert Itself After Vietnam

The Vietnam War produced an enormous backlash against unilateral presidential warfare.

Congress responded by enacting the War Powers Resolution of 1973 over President Richard Nixon’s veto.

The law requires consultation with Congress “in every possible instance” before introducing U.S. armed forces into hostilities or situations where imminent involvement in hostilities is clearly indicated. It also establishes reporting requirements and generally requires termination of unauthorized military involvement after a statutory period unless Congress authorizes continued operations (War Powers Resolution, 1973).

Presidents from both parties have questioned aspects of the resolution’s constitutionality.

Nevertheless, administrations generally submit reports consistent with it while carefully avoiding language that would concede Congress’s interpretation of presidential war powers (CRS, 2025b).

That uneasy compromise has survived for more than half a century.

But it has never resolved the underlying question:

How much war can a president wage before Congress must say yes?

Then Trump Bombed Iran

On June 21, 2025, Trump announced that U.S. forces had struck three Iranian nuclear facilities: Fordow, Natanz, and Isfahan.

The operation involved American military aircraft and munitions directed against facilities inside the sovereign territory of Iran.

The White House described the strikes as necessary to eliminate or severely degrade Iran’s nuclear capabilities and protect American national-security interests (The White House, 2025a).

Trump presented the operation as a spectacular military success.

Supporters argued that the president acted decisively against a serious threat and that limited strikes fell within presidential Article II authority.

Critics responded with a much simpler constitutional objection:

Congress had not authorized a war against Iran.

The Administration’s Legal Argument

The Trump administration subsequently provided Congress with its legal justification.

According to the administration, the president possessed constitutional authority to order the strikes because he determined that they served important national interests and because the anticipated nature, scope, and duration of the operation did not amount to “war” in the constitutional sense requiring prior congressional authorization (The White House, 2025b; CRS, 2025a).

That reasoning did not emerge from nowhere.

Previous administrations have used similar legal frameworks.

President Barack Obama’s administration relied upon comparable reasoning during the 2011 intervention in Libya, arguing that the limited character of the operation did not require prior congressional authorization under the Constitution.

Presidents have also ordered isolated missile strikes, retaliatory operations, rescue missions, counterterrorism raids, and other military actions without obtaining a declaration of war.

Trump therefore has a serious constitutional defense:

The presidency has accumulated substantial historical authority to conduct limited military operations without Congress first passing an authorization.

If impeachment is going to be considered, that defense cannot simply be ignored.

But Bombing Another Country Is Not a Minor Administrative Act

The opposing argument is equally serious.

American military forces attacked targets inside Iran.

Iran is a sovereign state.

Those targets were central to one of the most dangerous geopolitical disputes in the world.

A strike against Iranian nuclear facilities carried obvious risks of retaliation against American troops, American allies, shipping, energy infrastructure, and potentially the United States itself.

The operation therefore could have initiated a substantially larger war regardless of whether Trump intended one.

That is exactly why the Constitution placed war-making authority partly in Congress.

The Framers did not merely fear presidents deliberately launching enormous wars.

They feared executive decisions that could drag the country into war.

Once bombs fall, the other country gets a vote.

The president controls the American decision to strike.

He does not control Iran’s response.

Congress Had Not Authorized War With Iran

Congress had previously enacted Authorizations for Use of Military Force connected to the September 11 attacks and the Iraq War.

Neither constituted a general authorization to wage war against Iran.

The administration primarily defended the June 2025 strikes through Article II presidential authority rather than claiming Congress had already authorized an Iranian war (CRS, 2025a).

That fact makes the constitutional dispute unusually clean.

The question is not principally whether an old congressional authorization can be stretched to cover a new enemy.

The question is whether the president himself possessed sufficient constitutional authority to order the operation.

Trump said yes.

Some members of Congress said no.

Congress Responded With War Powers Measures

Members of Congress introduced measures intended to require congressional authorization for continued or additional hostilities involving Iran.

Senator Tim Kaine introduced S.J.Res. 59 directing the removal of U.S. armed forces from hostilities against Iran unless Congress specifically authorized those hostilities (U.S. Senate, 2025).

In the House, Representative Thomas Massie, a Republican, joined Democratic Representative Ro Khanna in introducing a corresponding war-powers resolution asserting that Congress—not the president alone—possesses the constitutional authority to decide whether the United States enters war with Iran (U.S. House of Representatives, 2025b).

That bipartisan opposition is significant.

The dispute was not simply Democrats objecting because Trump is a Republican.

Some Republicans also argued that Congress had been bypassed.

Then Came an Article of Impeachment

Representative Al Green went further.

On June 24, 2025, Green introduced H.Res. 537, accusing Trump of committing a high crime and misdemeanor by abusing presidential power and usurping Congress’s constitutional authority to declare war when he ordered military strikes against Iran without congressional authorization (U.S. House of Representatives, 2025a).

The House did not embrace Green’s argument.

On June 24, it voted 344–79 to table the impeachment resolution, with 128 Democrats joining Republicans in effectively stopping immediate consideration (U.S. House of Representatives, 2025c).

That vote matters.

Congress was plainly nowhere near a consensus that the Iran strikes justified impeachment.

Any honest account has to say so.

But tabling an impeachment resolution is a political judgment.

It is not a Supreme Court ruling establishing that the president possessed unlimited constitutional authority.

The underlying separation-of-powers question remains.

A Bad Policy Decision Is Not Necessarily Impeachable

This series has repeatedly returned to the same limitation because it matters.

Congress should not impeach presidents simply because legislators disagree with presidential policy.

A military operation can be foolish without being impeachable.

It can fail without being impeachable.

It can be strategically reckless without necessarily constituting a high crime or misdemeanor.

Presidents must possess operational flexibility.

If American forces are attacked, nobody seriously expects the president to wait for a week-long congressional debate before defending them.

If intelligence reveals an imminent attack, the commander in chief must possess some capacity to act.

The Constitution cannot require paralysis.

The difficult case is different.

It is a deliberate military operation against another sovereign country, undertaken without an immediate attack requiring instantaneous defense, where Congress has not authorized hostilities.

At that point, the constitutional allocation of war powers becomes unavoidable.

The Problem Is Larger Than Trump

Trump’s critics should recognize something uncomfortable.

Presidents did not acquire expansive unilateral war-making authority in January 2017 or January 2025.

Congress helped create this situation.

For decades, legislators from both parties have tolerated presidential military actions without declarations of war.

Sometimes Congress has provided broad authorizations and then allowed presidents to interpret them expansively.

Sometimes it has funded military operations after they began.

Sometimes it has complained without taking decisive legislative action.

Sometimes lawmakers have preferred letting presidents make dangerous decisions because doing so allows Congress to avoid political responsibility.

That history weakens any simplistic claim that Trump’s Iran strike suddenly invented an unconstitutional presidency.

But it strengthens another argument.

Eventually a constitutional boundary that is never enforced ceases to function as a meaningful boundary.

What Would Make This Impeachable?

The strongest impeachment argument would not be:

Donald Trump bombed Iran, and bombing Iran was bad.

The argument would instead be structural.

Trump knowingly exercised a power the Constitution assigns to Congress.

Congress had not authorized hostilities.

There was no immediate circumstance requiring instantaneous defensive action.

The operation carried a foreseeable risk of expanding into major warfare.

And the president nevertheless determined by himself that the United States would initiate military action against another sovereign state.

If Congress concludes that those facts constitute a deliberate usurpation of legislative authority, then the impeachment question becomes substantial.

The Congressional Research Service has repeatedly recognized that disputes over presidential initiation of hostilities remain among the most difficult unresolved questions in constitutional law (CRS, 2025a, 2025b).

Impeachment would therefore not be punishment for foreign policy.

It would be Congress defending its own constitutional authority.

The Cost of No Accountability

Imagine the precedent carried forward.

A future president decides China poses an intolerable threat.

American aircraft strike Chinese installations.

Congress was not consulted.

Another president decides North Korea’s nuclear program has become unacceptable.

Bombers attack North Korean facilities.

Congress was not consulted.

Another president decides Venezuela threatens American security.

Missiles strike Caracas.

Congress was not consulted.

Each president points backward.

Iran was bombed without prior congressional authorization.

Libya was attacked without a declaration of war.

Other presidents launched strikes.

Congress tolerated it.

Therefore the president possesses the authority.

That is how constitutional power migrates.

Not usually through a dramatic announcement that the Constitution has been abolished.

It migrates through precedent.

One president pushes the boundary.

Congress does nothing.

The next president starts from the new boundary and pushes again.

Eventually Article I may continue saying that Congress has the power to declare war while presidents possess the practical power to initiate virtually any war they choose.

At that point the constitutional language remains.

The constitutional restraint does not.

The danger is especially severe because warfare is unlike most presidential decisions.

A regulation can be repealed.

A budget can be amended.

An executive order can be rescinded.

A military strike cannot be unlaunched.

People die.

Other governments respond.

Alliances activate.

Markets react.

Armies mobilize.

Wars expand.

That is why the decision to begin hostilities was never supposed to belong casually to one person.

Trump’s Iran strikes therefore force Congress to confront a question it has avoided under presidents of both parties:

Does Congress actually possess the war power the Constitution gives it, or has decades of congressional surrender transferred that power to the presidency?

If the answer is the latter, then Donald Trump is not the endpoint of the problem.

He is another step in a constitutional transformation that has been occurring for generations.

And the president who eventually inherits the fully developed version of that power may be far more dangerous than Trump.

References

Congressional Research Service. (2025a). Presidential power to use military force: Selected legal issues. U.S. Congress.

Congressional Research Service. (2025b). The War Powers Resolution: Concepts and practice. U.S. Congress.

Hamilton, A. (1788/1961). Federalist No. 69. In C. Rossiter (Ed.), The Federalist Papers. New American Library.

Madison, J. (1793/1906). Helvidius No. 1. In G. Hunt (Ed.), The writings of James Madison (Vol. 6). G. P. Putnam’s Sons.

The White House. (2025a, June 21). President Trump announces successful strikes on Iranian nuclear facilities. Executive Office of the President.

The White House. (2025b). Report to Congress consistent with the War Powers Resolution concerning United States military operations against Iranian nuclear facilities. Executive Office of the President.

U.S. Constitution, art. I, § 8; art. II, § 2.

U.S. House of Representatives. (2025a). Impeaching Donald John Trump, President of the United States, for high crimes and misdemeanors (H. Res. 537, 119th Cong.).

U.S. House of Representatives. (2025b). Directing the removal of United States Armed Forces from hostilities against Iran that have not been authorized by Congress (H. Con. Res. 38, 119th Cong.).

U.S. House of Representatives. (2025c, June 24). Roll call vote on motion to table H. Res. 537, 119th Congress.

U.S. Senate. (2025). A joint resolution directing the removal of United States Armed Forces from hostilities against the Islamic Republic of Iran that have not been authorized by Congress (S.J. Res. 59, 119th Cong.).

War Powers Resolution, 50 U.S.C. §§ 1541–1548 (1973).