The NATO Treaty Does Not Supersede the Constitution

A group of senators is challenging the conventional interpretation of Article 5's an-attack-on-one-is-an-attack-on-all provision.


As the White House pushes for the admission of Ukraine into NATO, a group of senators is questioning a common interpretation of the security pact's founding treaty.

On June 22, Sen. Rand Paul (R–Ky.) and Reps. Chip Roy (R–Texas) and Warren Davidson (R–Ohio)* introduced legislation to clarify America's commitment in the case of an attack on a fellow NATO member, emphasizing that "if the President deems it necessary to engage United States forces in hostilities in order to restore or maintain the security of the North Atlantic area as stated in Article 5, such action does not supersede the constitutional requirement that Congress declare war or authorize the use of military force prior to the United States engaging in hostilities."

Paul explained the move in an article for Responsible Statecraft. "For decades, many legislators have incorrectly interpreted Article 5 as an obligation that unquestionably commits the United States to provide military support should a NATO ally be attacked," he wrote. "The Constitution grants to Congress the sole authority to determine where and when we send our sons and daughters to fight. We cannot delegate that responsibility to the president, the courts, an international body, or our allies."

Article 5 of the NATO treaty declares that "an armed attack against one or more of [the group's members] shall be considered an attack against them all." Officials have traditionally interpreted this as a requirement to intervene if any of NATO's 30 members are attacked. Thus, for example, an errant Russian missile landing in Poland could allow a U.S. president to unilaterally authorize military force against Russia.

But while Article 5 commits NATO allies to defend each other, it stops short of demanding military aid, stating that a responding party can take "such actions as it deems necessary, including the use of armed force." 

According to Article 11 of the treaty, the agreement's provisions should be carried out through the "respective constitutional processes" of NATO countries. For the U.S., this means that any decision about military intervention requires congressional approval.

"There's no conflict between the treaty and the Constitution. If there were, of course, the Constitution would prevail," explains Michael J. Glennon, a professor of constitutional and international law at Tufts University. "This debate has made clear over the course of the 100 years since the Treaty of Versailles came before the Senate that the House of Representatives cannot constitutionally be cut out of the decision to go to war. That's the bottom line."

Despite this clear language, the prevailing view is that a military response is an "ironclad" aspect of the agreement. President Joe Biden has reinforced this idea by claiming, "An attack against one is an attack against all. It's a sacred oath. A sacred oath to defend every inch of NATO territory."

The supposed sanctity of the prevailing view has prompted accusations of weakness against those who question it. When Paul previously introduced this legislation in 2022 as an amendment to the resolution backing the ascension of Sweden and Finland to NATO, Sen. Mitt Romney (R-Utah) declared it "wobbly on Article 5."

"I think that there's a real pervasive ignorance of foreign affairs among many members of the legislature. They have this magical sense of deterrence, that deterrence is cheap," says Justin Logan, director of defense and foreign policy studies at the Cato Institute. "The framers of the Washington Treaty didn't think that way. They thought that international politics was a really dangerous business."

Given the potential for a conflict with a nuclear-armed power, it is ever more important to ensure that military action is deliberative and in the country's interest.

*CORRECTION: This original version of this article mischaracterized Roy and Davidson's positions in Congress.