Separation of powers is an elementary concept in American government, known to everyone from grade schoolers to Supreme Court justices. In recent years, however, it’s become as well-ignored as it is well-known — perhaps more so. That’s why the Yemen War Powers Resolution (S.J. Res. 54) and the coalition surrounding it was so remarkable.

The bipartisan team of Sen. Mike Lee, R-Utah, and Bernie Sanders, I-Vt., introduced a joint resolution that calls for a vote in the full chamber within weeks on removing unauthorized U.S. armed forces from hostilities in Yemen. That vote happened and revealed which legislators want to protect Congress’ constitutional responsibility to declare war and which legislators are willing to neglect the Constitution in favor of political expediency.

Ironically, however, opponents of the resolution have also made use of the Constitution, contending that these senators are “pretending to be commanders in chief” — a role delegated to the president in Article II, Section 2, Clause 1 of the Constitution. But those who make these claims ignore a key stipulation made in that definition. The president is commander in chief when — and only when — “called into the actual Service of the United States.”

Who calls U.S. military “into the actual Service of the United States”? Per Article I, Section 8, Congress — and only Congress — can declare war. This resolution is not an attempt by senators to be commanders in chief. Rather, it simply reinforces that the Constitution delegates the power to declare war to Congress.

Those supportive of this unauthorized military action accused the senators supportive of S.J. Res. 54 as being “indifferent to these strategic stakes (of U.S. support to the Saudi-led coalition) as they try to enfeeble executive war powers.” Here again, however, they’re completely wrong: The resolution is entirely agnostic on strategy. If the strategy of U.S. involvement in Yemen is so important that it must continue, the resolution allows Congress ample time to debate and authorize these measures.

Indeed, you would think that the Department of Defense would leap at the opportunity to make its case directly to the deliberative chambers of Congress to request a true authorization for a worthwhile conflict, defending the intervention in Yemen as a crucial part of U.S. strategy. But it has not.

Instead, the Department of Defense took extraordinary pre-emptive measures to combat this resolution — penning multiple letters to the Senate, making unsettling assertions at hearings and holding closed-door member briefings. The department's unwillingness to make an honest case for authorization of this conflict to Congress is a clear indication that the department knows it has overstepped its constitutional bounds and is worried about its power being stripped away by the Senate.

If the Department of Defense's intervention in Yemen is legal, as it claims, such backlash to the resolution would have been unwarranted. To prove this point, Defense Secretary James Mattis acknowledged the unauthorized nature of the conflict in a March 14 letter to the Senate, stating explicitly that “Neither President Obama nor President Trump authorized the use of U.S. military force against the Houthis.”

Instead of recognizing this admission of unconstitutionality, however, those who attacked these senators focused on the Pentagon’s subsequent argument — and highly questionable legal stance — that the U.S. aid to the Saudi coalition is within the scope of the president’s Article II powers and does not constitute hostilities as such. They contend that for conflict to be considered “hostilities,” our armed forces must be in active combat on the ground.

This notion is completely incompatible with the way modern military conflicts work. What’s more, it also flies directly contrary to existing law. Section 8(c) of the War Powers Act of 1973, which S.J. Res. 54 invokes, defines the level of military involvement necessary to invoke its restraints as “the assignment of members of such armed forces to command, coordinate, participate in the movement of, or accompany the regular or irregular military forces of any foreign country or government where such military forces are engaged.” Intelligence sharing, midair refueling of Saudi planes used to bomb Yemen and actual targeting assistance in these airstrikes — all these steps undoubtedly qualify as “hostilities.”

The most pernicious argument of all, however, claims that passing this resolution would have been a “gratuitous gift to Iran.” Again, the resolution did not touch the issue of strategy. Congress was and still is perfectly at liberty to support continued action in Yemen — a fact Lee and Sanders are well aware of. These men were simply attempting to hold our leaders accountable to the Constitution and force a responsible conversation on military intervention, which they will undoubtedly continue to do. This kind of accountability and responsibility is a gift to members of our armed forces, our allies and, above all, our citizens. It is in no imaginable way “a gift to Iran.”

James Madison once wrote, “In no part of the Constitution is more wisdom to be found than in the clause which confides the question of war or peace to the Legislature, and not to the executive department.” Lee and Sanders, unlikely duo though they be, are doing their rightful duty by requiring Congress to answer to the Constitution’s question of war or peace.