For over a thousand years, Sunni and Shia Muslims have been fighting and killing each other around the world. And since the Iranian Revolution of 1979, much of that fighting has occurred as part of an ongoing proxy war between Iranian-backed Shia forces and Saudi Arabian-backed Sunni forces.

On March 26, 2015, this centuries-long conflict continued when Saudi Arabia’s military killed 17 people in an attack on Shia Houthi forces that were in control of the Sana'a International Airport in Yemen. The Iranian-backed Houthis had driven Saudi-backed President Abd Rabbu Mansour Hadi out of the country. Saudi Arabia was intent on putting him back in power.

Ideally, this would be of little concern to the United States. But President Obama had just given Iran $1.7 billion as part of his nuclear deal with the theocratic regime—money that Iran immediately began to spend on proxy wars throughout the Middle East.

Obama did not want to alienate our traditional Saudi allies in the region, so without any congressional debate he began supporting the Saudi war in Yemen by providing aerial refueling to Saudi jets and intelligence for targeting. Houthi forces responded by firing missiles at a U.S. Navy destroyer. U.S. forces responded by destroying three radar sites with cruise missiles.

Since the Saudi war in Yemen began, more than 10,000 civilians have died and another 40,000 have been wounded. Fifteen million people can’t access clean water and 17 million people—about 60 percent of the country’s population—are at risk of starvation.

Congress has voted to send more than $768 million in humanitarian aid to Yemen, but it never voted on the military force that created the humanitarian crisis in the first place.

One can debate the wisdom of United States involvement in Yemen. What is beyond debate is that our current support for the Saudi war in Yemen is unconstitutional. Congress should have a debate and a vote on the matter.

Article I, Section 8 of the Constitution clearly states that, “Congress shall have power to … declare war.” No such declaration was ever made, or even proposed, for the war in Yemen.

And while Article II of the Constitution identifies the president as commander-in-chief of the Army and Navy of the United States, it is generally understood that this only gives the president power to order military operations in emergency situations. The three-year-old civil war in Yemen, which poses little to no danger to the United States, does not qualify as an emergency situation.

That is why I joined Sens. Bernie Sanders (I-VT) and Chris Murphy (D-CT) last week to introduce a joint resolution pursuant to the War Powers Act of 1973 that would force the president to remove United States forces from the conflict.

Our resolution will become ripe next week, giving us the power to file a discharge motion and force a full vote on the matter in the Senate.

Opponents of this resolution assure us that our military campaign in Yemen is worth it. If that is so, surely they can defend it before the public and muster the votes necessary to provide the administration with an authorization for use of military force.

President Trump won the election last year after promising to reevaluate our nation’s foreign policy priorities. If we continue to insert ourselves into conflicts with no direct impact on U.S. national security, we divert resources—assets, time, and most importantly, lives—that could be better spent elsewhere.

This resolution opens up the door for President Trump to do that reevaluation now, hand-in-hand with Congress.