On July 3, PBS News Hour reporter Jane Ferguson was in Yemen covering the world’s worst humanitarian catastrophe. She spoke with Dr. Ali Al Motaa, a Yemeni professor, who told her: “The missiles that kill us, American-made. The planes that kill us, American-made. The tanks, Abrams, American-made. You are saying to me, where is America? America is the whole thing.”

He wasn’t exaggerating. Five weeks later, Saudi planes bombed a school bus full of children heading back to school from a picnic, killing forty children and eleven adults. According to a CNN report, the bomb that hit the bus was made in the US. The Saudi government’s official response to widespread international public outrage was to insist that the bombing of the school bus was a “legitimate” military action.

More than 10,000 civilians have been killed in the conflict, mainly by airstrikes launched by Saudi Arabia and the United Arab Emirates, with the backing of the US, since these attacks began in 2015. Unfortunately, the direct killings from dropped bombs are only part of the death toll. The destruction also wrought on water supplies and sewage systems has resulted in the deaths of thousands in one of the world’s worst cholera epidemics in modern history. Besides destroying infrastructure, the Saudis have imposed a blockade that has cut access to food, clean drinking water, medicine, and other necessities for treatment.

Millions of Yemenis, including children, are malnourished, and an estimated 8.4 million are on the verge of famine. Fifty thousand children have died in 2017 alone due to preventable causes from the war, including hunger and disease. Even so, Dr. Motaa was understating the responsibility of the United States for these horrors.

It is true that, from 2013 to 2017, Washington supplied more than 60 percent of Saudi arms, including the planes that Donald Trump triumphantly announced in March as his own business success for America. While many other countries sell arms to Saudi Arabia, including Britain, France, Germany, and Canada, the US has increasingly grabbed the lion’s share of the market—up from 38 percent in 2012. Thanks largely to the demands for matériel to sustain its offensive actions in Yemen, Saudi arms imports have nearly quadrupled during these five years.

But the US is doing much more than selling weapons. The American military is actively participating in the war and bears a direct responsibility for the atrocities that result. US planes are refueling the Saudi and allied bombers in mid-air. The US military is supplying intelligence and logistics, and also targeting information. (It has not yet been determined whether US support was involved in the August air strike on the school bus.) US Army Green Berets have also been deployed in the war, across the border in Saudi Arabia, to help Saudi forces destroy caches of ballistic missiles and launch sites. The US, together with the UK and France, are using their weight in the UN Security Council to block any resolution mandating a ceasefire.

None of this military participation is permitted under the US Constitution. Article I, section 8 clearly reserves for Congress the power to declare war and to decide on US military action abroad. No court decision (including by the Supreme Court) has altered that original meaning. To be sure, presidents have sometimes ignored the Constitution and ordered military actions abroad—like this one, which began during the Obama administration—without authorization from Congress, but neither Congress nor the judicial branch has granted the president that power.

On the contrary, in 1973, after more than a decade of US involvement in Vietnam, which at its height had seen the deployment of more than half a million US troops without a formal declaration of war, Congress passed the War Powers Resolution to “insure that the collective judgment of both the Congress and the President will apply to the introduction of the United States Armed Forces into hostilities.” The legislation states:

The constitutional powers of the President as Commander-in-Chief to introduce United States Armed Forces into hostilities, or into situations where imminent involvement in hostilities is clearly indicated by the circumstances, are exercised only pursuant to (1) a declaration of war, (2) specific statutory authorization, or (3) a national emergency created by attack upon the United States, its territories or possessions, or its armed forces.

If none of these conditions are met, the military action is therefore unconstitutional. But Congress has not directly used its power to force the president to remove US armed forces from participation in a war. Until now.

The 1973 War Powers Resolution has a very important provision that legislates for when the president has introduced armed forces into unauthorized hostilities: in such circumstances, a single member of Congress can force a debate and a vote on the military action. This debate and vote cannot be blocked by the leadership of either house.

In November of last year, members of Congress, led by Representatives Ro Khanna (Democrat of California) and Mark Pocan (Democrat of Wisconsin), with the Congressional Progressive Caucus, and joined by Walter Jones (Republican of North Carolina), and Thomas Massie (Republican of Kentucky), used the statute to try to force a vote on the war in Yemen. They didn’t get an up-or-down vote on the war, because of procedural manipulation by House leadership; but by a margin of 366 to 30, the House voted in an amended, compromise bill to recognize for the first time that the US was engaging in the war through its mid-air refueling and targeting assistance, and that this military participation was unauthorized.

Then, in February of this year, Senators Bernie Sanders (Independent of Vermont), Mike Lee (Republican of Utah), and Chris Murphy (Democrat of Connecticut) used the War Powers Resolution for the first time to force a vote in the Senate. It lost by a margin of 55–44, but it was clear that Congress was closing in on the war. Last week, a bigger and more influential group in the House joined in to announce that they would try again. Among the cosponsors of the renewed effort is Adam Smith (of Washington State), who is the ranking Democrat on the House Armed Services Committee. If the Democrats win the House in November’s mid-terms, he is expected to chair that powerful committee, which oversees the Pentagon.

The Saudis are clearly watching what is happening in Congress with alarm. In August, they waited until Congress went into recess before they began bombing Hodeidah, the main port where most of Yemen’s food enters the country. But others are watching, too. Last week, Spain canceled the sale of 400 laser-guided bombs to Saudi Arabia. The Spanish government said it was concerned that they could be used to target civilians. Germany, Sweden, Norway, Finland, and Belgium have also suspended some arms sales to Saudi Arabia.

But it is the US support for and participation in the war that will be decisive. Bruce Riedel, who directs the Intelligence Project at the Brookings Institution, said in April 2016 that if the US and UK “tonight told King Salman that this war has to end, it would end tomorrow.” Apart from anything else, the US has hundreds of refueling planes that have, reportedly, participated in 7,564 refueling “events” during the war; no other country has comparable capacity.

This war, like most American military ventures, has nothing to do with the national security of the United States. The Houthis that Washington is trying to defeat, because they are supported by Iran, the Saudis’ regional rival, are also fierce opponents of al-Qaeda; in contrast, Saudi Arabia has provided support for al-Qaeda and other terrorist organizations. This support is anything but historical: in August, the Associated Press reported that the Saudi coalition “cut secret deals with al-Qaeda fighters, paying some to leave key cities and towns and letting others retreat with weapons, equipment and wads of looted cash… Hundreds more were recruited to join the coalition itself.”

The war in Yemen is primarily an internal civil war driven by local interests; this includes a regional conflict between the North and the South, which were separate countries before 1990. The Saudis have intervened on the side of the central government against the Houthi rebels, whom they see as a threat to their domination of the Arabian peninsula. Iran has backed the Houthis, although it is not clear to what extent, and Tehran certainly does not control the Houthis. Yet the Iranian support is the pretext for US intervention, especially for avowed Iran foes such as Defense Secretary Gen. James Mattis, President Trump himself, as well as neoconservatives generally, including National Security Adviser John Bolton. Behind the Iran pretext, the motive for US participation in this war is the usual one: maintaining American power and influence in the region.

It is unfortunate that the major media have given so little attention to the battle in Congress, because that is how this war will be ended and potentially millions of lives saved. The omission is not because US journalists are particularly sympathetic to this war. The New York Times editorial board, in a piece headlined “Saudis try to starve Yemen into submission,” effectively accused the US government of complicity in “war crimes.”

But most journalists seem to accept the imperial presidency as a political reality, and do not seem to realize that Congress has constitutional authority over decisions of war and peace and is in the process of reclaiming that authority. The implications of this historic shift would be enormous, as big as the destruction, mass slaughter, and chaos that has been caused by the endless series of wars and US military interventions unleashed since the 9/11 attacks seventeen years ago.