For more than 40 years, the United States and Iran have had a troubled relationship. Because of the Iranian regime’s insistence on spreading terror throughout the region and its efforts to develop nuclear weapons, multiple administrations have considered a broad range of options — both military and diplomatic — to counter these threats.

The legality of many of these actions has been murky at best, and this has not always been the fault of just the executive branch. Far too often, Congress has been the one to shirk its responsibility to debate the proper use of force to meet global threats.

That needs to change. That’s why we have partnered to introduce a resolution that would prohibit war with Iran without congressional authorization.

There is no more consequential decision than whether to go to war, which is why the Framers of the Constitution placed safeguards to prevent a rush into war. James Madison, the principal drafter of the Constitution, wrote that the history of mankind showed that the executive branch is “most interested in war, & most prone to it.”

For this reason, he noted that the Constitution, “with studied care, vested the question of war” in the legislature. Once initiated, the power to carry out military action does flow to the president as commander in chief. And the president always has the power to defend the nation from imminent attack. But even when the president acts unilaterally in response to an attack, that action must be brief and limited to addressing a specific threat. Any action beyond that scope requires an authorization by Congress.

Much of our nation’s recent interactions with Iran, both military and diplomatic, have been carried out by the executive with no congressional authorization. At a briefing last week, the administration — like other administrations of both parties before it — was infuriatingly dismissive of the role of Congress in decisions about war. Administration officials even suggested that congressional debate might hurt the morale of U.S. troops.

They have it backward. Congressional debate and deliberation are designed precisely to protect our troops and their families. After more than 18 years of continuous war in the Middle East, we know too well the sacrifices that are made by our best and brightest. They face injury and death and the shock of losing comrades in arms. And their friends and families face the anxiety of wondering what will happen and the heavy burden of providing care to those affected. If the United States is to order our troops into harm’s way again, we should at least have an open debate about whether a war with Iran, or indeed any war, is truly in our national interest.

Our resolution puts a simple statement before the Senate. We should not be at war with Iran unless Congress authorizes it. If senators are unwilling to have this debate — because a war vote is hard or opinion polls suggest that their vote might be unpopular — how dare we order our troops to courageously serve and risk all?

Op-Ed With Senator Tim Kaine (D-VA) originally published by the Washington Post