This is what is sometimes known as a “naked Article II” assertion of presidential power. That is, the executive branch is claiming the right to use armed force without reference to any authorization from Congress. Kirby made the same case in almost exactly the same words in February when Joe Biden bombed northeastern Syria. “The President took this action pursuant to his Article II authority to defend U.S. personnel,” he said at the time.
This may seem confusing, given that Article I, Section 8 of the U.S. Constitution declares that “the Congress shall have Power … To declare War.”
The rationale for this clause can be found in a famous 1793 polemic by James Madison, considered the father of the Constitution, which had been ratified just four years earlier. Madison argued the power to declare war must be “fully and exclusively vested” in Congress because history showed that “the executive is the department of power most distinguished by its propensity to war: hence it is the practice of all states, in proportion as they are free, to disarm this propensity of its influence.”
Madison therefore called for a “rigid adherence to the simple, the received and the fundamental doctrine of the constitution, that the power to declare war including the power of judging of the causes of war is fully and exclusively vested in the legislature: that the executive has no right, in any case to decide the question.”
This perspective constrained the executive branch to some limited extent through the end of World War II. Then, in 1950, President Harry Truman ordered hundreds of thousands of U.S. troops to Korea with no congressional authorization. His State Department instead issued a memo explaining why “the President’s authority to send the Armed Forces outside the country is not dependent on Congressional authority.” Why? Because “the President’s control over the Armed Forces of the United States is based on article 2, section 2 of the Constitution.” Article II, Section 2 states, “The President shall be Commander in Chief of the Army and Navy of the United States.”
The 1964 Gulf of Tonkin Resolution, passed under false pretenses, did provide some congressional authorization for the subsequent massive expansion of the Vietnam War, then already in progress. However, there was never any congressional support at all for America’s secret military campaign against Vietnam’s next door neighbor, Cambodia. The U.S. dropped about half a million tons of bombs on the poor peasant nation, about the same amount we used in the entire Pacific theater during World War II. The Nixon administration explained that this was fine and perfectly legal because the Korean War “stands as a precedent for executive action in committing United States armed forces to extensive hostilities without any formal declaration of war by Congress.” The U.S. had “in no sense gone to ‘war’ with Cambodia,” and Nixon didn’t need any authorization from Congress, given “the constitutional designation of the President as Commander in Chief.”
This perspective on presidential power has since become doctrine for Republicans and many Democrats. Congress authorized the Gulf War in 1991, but then-Secretary of Defense Dick Cheney felt this was unnecessary. “We had the Truman precedent from the Korean crisis of 1950,” Cheney said. “From a constitutional standpoint, we had all the authority we needed.”
The Justice Department provided Cheney and the rest of the George W. Bush administration with a legal justification for pure presidential power soon after the 9/11 attacks. Article II, it said, establishes that “the Founders entrusted the President with the primary responsibility, and therefore the power, to use military force in situations of emergency.” So the president did not need congressional authorization to attack “terrorist organizations or the States that harbor or support them, whether or not they can be linked to the specific terrorist incidents of September 11.”
That said, presidents have generally preferred to do a sort of legal two-step on this issue. They like to say they are acting “in accordance with” some kind of congressional authorization, even as they say Article II means they don’t need it. 2001’s Authorization for Use of Military Force, passed with a sole “no” vote after the 9/11 terrorist attacks, has proven particularly useful in this regard. According to a 2018 Congressional Research Service report, the 2001 AUMF had been cited by presidents 41 times: 18 by the Bush administration, 21 by Obama, and twice by Trump.
But even the 2001 AUMF couldn’t be stretched to cover the U.S. participation in the 2011 overthrow of Libya’s government. The Obama administration’s legal rationale for that was simply Article II. Then Trump bombed Syria on several occasions, explaining in a 22-page 2018 memo that “Article II provides the President with the authority to direct U.S. military forces in engagements necessary to advance American national interests abroad.”
After Washington officials witnessed Trump’s extraordinary recklessness — which during his first year in office could have genuinely led to nuclear war with North Korea, just on his sole decree — there was a brief window when it appeared the next administration might have limits placed on its war powers, either by itself or by Congress or both. But with Biden’s action since taking office, that window appears to have closed. It’s not surprising, but America’s continuing retreat from what Madison called “the practice of all states, in proportion as they are free,” is nonetheless extremely ominous.