Some in Washington are insisting that President Trump’s strike on Iran is unconstitutional because only Congress has the power to declare war. Yet examples dating back to 1798 testify to the executive’s unilateral authority to defend against foes — a power embodied in the so-called Nuclear Football.

A Kentucky Republican, Congressman Thomas Massie, posted on X that Saturday’s action was “not constitutional.” A New York Democrat, Congresswoman Alexandria Ocasio-Cortez, called it “a grave violation of the Constitution and congressional war powers” that’s “absolutely and clearly grounds for impeachment.”

The Constitution doesn’t sustain these charges. It gives Congress, in Article I of the Constitution, the power to declare war. It makes the president “commander-in-chief” in Article II, with the power to issue orders and direct the military.

Lieutenant Colonel Robert “Buzz” Patterson carried the Presidential Emergency Satchel, or Nuclear Football, for President Clinton. He told The New York Sun that it’s “a perfect example” of the roles on either end of Pennsylvania Avenue: Presidents can deploy atomic bombs; Congress cannot.

“There are instances,” Mr. Patterson said, “when seeking congressional approval simply isn’t feasible. Presidents have a finite time to make decisions. Can you imagine the congressional trainwreck of politicians preening in front of cameras for weeks?”

In the “best-case scenario,” Mr. Patterson said, the president “has 20 minutes to decide to retaliate. There’s no time for phone calls to Congress, TV interviews, op-eds, or debate on the floor. None. That’s why he/she is the commander-in-chief. They have command.” 

The “Restricting First Use of Nuclear Weapons Act” has been introduced in every Congress since 2016. Expect a court challenge based on Article II if it ever passes. In the meantime, since it’s constitutional for a president to drop atomic bombs, it’s hard to see how bunker-busters are forbidden. 

President John Adams was the first to apply military force without congressional approval. That was in the quasi-war of 1798 against France. His immediate successors, Presidents Jefferson and Madison — “Father of the Constitution” — followed suit in the Barbary wars. 

Both President Johnsons and the two Presidents Roosevelt as well as Presidents Monroe, Polk, and Wilson were among many others who acted alone. The reverse situation almost occurred in 1898 when a hawkish Congress threatened to declare war on Spain and force President McKinley to prosecute a war he hoped to avoid.

There’s been no formal declaration of war since 1942. That the Constitution doesn’t lay out parameters for one indicates that the Founders expected presidents wouldn’t need it for small skirmishes. In 1973, reacting to the bombing of Cambodia, Congress tried to restrain presidential authority, passing the War Powers Resolution over President Nixon’s veto. 

Succeeding presidents have agreed that the Act is unconstitutional. When President Obama attacked Libya, Pakistan, Yemen, and Somalia, he weathered the same bipartisan accusations now leveled at Mr. Trump. Congress didn’t pursue impeachment or cut off funds as it did to end the Mexican and Vietnam wars. 

Despite their objections, presidents have abided by the War Powers Resolution’s simple provisions. It requires notification of Congress within 48 hours of military action and places a limit of 60 to 90 days on deployments.

Mr. Trump informed Speaker Johnson; the Senate majority leader, John Thune; the Senate minority leader, Charles “Chuck” Schumer; and the House minority leader, Hakeem Jeffries, before Saturday’s “Operation Midnight Hammer.” 

Mr. Johnson posted on X that “the commander-in-chief evaluated that the imminent danger” posed by Iran “outweighed the time it would take for Congress to act,” as would be the case with incoming ICBMs. 

Congress also recognized presidential power with the Authorization for Use of Military Force of 2001. It cleared presidents “to use all necessary and appropriate force against those nations, organizations, or persons he,” not Congress, “determines” were responsible for attacks on America.

The authorization assented to presidents acting “to prevent any future acts of international terrorism” of the sort that Iran has committed since 1979. The language was broad and invited abuse, which is one reason to return to declarations of war aimed at enemy states. 

The Constitution diffuses power, giving Congress the authority to declare and fund wars. Framers like Madison knew that commanders-in-chief would sometimes need to act against immediate threats. It’s why presidents have the launch codes, but no member of Congress can lay a finger on the Nuclear Football.