What will Donald Trump do with American foreign policy? It's impossible to know, especially in regards to the Middle East. He has articulated views that are war-weary and views that are hawkish. Many observers treat the Middle East as a zero-sum conflict between Shia and Sunni powers, in which the U.S. should mostly stick with its Sunni allies. But Trump has criticized America's Sunni ally Saudi Arabia as a costly dependent of the United States. At the same time he has also talked about ripping up President Obama's deal with Shia-dominated Iran.

But if Trump does want to bring some positive change to U.S. foreign policy, he should seek to end the war in Yemen.

Saudi Arabia announced on Monday that it would not extend a 48-hour cease-fire in its war there. The war doesn't make many headlines in the United States, even though the U.S. is directly involved in helping the Saudi military fire at targets in Yemen and blockade that country.

Here is the background. Yemen has been a divided country. The Houthis, a group of tribesmen from the north of the country who practice a variety of Shia Islam called Zaydi, had joined other groups in the Yemeni revolution of 2011. But they found themselves excluded from power again when the transitional government was formed. That government was weak and seen as a cat's paw of Saudi Arabia and the U.S. and so they rebelled again in 2012. Eventually the Houthis captured the capital city, Sanaa. The Houthis did have some support from Sunni Muslims in other parts of the country, who were dissatisfied with the transitional government.

Arrayed against the Houthis are Saudi Arabia and a number of Sunni Arab states who support the presidency of Abdrabbuh Mansour Hadi. At this point Hadi's presidency is a lost cause as he has so little domestic support. But the combatants continue fighting, in part because they see the conflict as one theater in the broader struggle between Sunni and Shia political power that is raging across in the Middle East.

The U.S. role in the war is substantial. Saudi Arabia buys most of its weapons from the United States. Its pilots are trained by the United States. And the United States refuels Saudi planes in the air. The U.S. military is widely believed to be helping the Saudis choose targets. And U.S. special forces are on the ground in Yemen, ostensibly to fight local al Qaeda outfits. But just as in Syria, the U.S. finds itself committed to the downfall of a Shia government, while at the same time working to degrade the ability of al Qaeda to benefit from the fall of that same government. The Saudi coalition routinely bomb civilian targets like hospitals or food production facilities. In turn, the Houthis have resorted to extreme tactics as well.

The humanitarian effect of the war has been disastrous. Over three million Yemeni people have been displaced from their homes. Another 14 million are threatened with what the U.N. calls "food insecurity," because blockading efforts and the war itself have a devastating effect on the import-dependent food supply of the nation.

But the United States does not have to continue exacerbating the situation. It's an immoral and unjust war on a population that does not threaten the United States. It contributes to the disorder and chaos in the Middle East that has benefited international terror groups. An end to the conflict would at least begin to ratchet down tensions between Saudi Arabia and Iran. (Although any realist must admit they may tick up again in Syria or in any number of conflict sites in the Middle East.)

So what should Trump do?

First, he should try an aggressive push to get Saudi Arabia to drop its support for Hadi and reduce their expectations for shaping and controlling a post-war government in Yemen. If the Saudis do not want to do that, the U.S. can and should cease all military support operations for Saudi Arabia in the war zone.

Trump's advisers may come back and explain that giving the Saudis a cold shoulder is a problem. Maybe they'll say that while Saudi Arabia may fund ISIS and other terrorist groups in Syria and Iraq, it's still a check on Iran in the region. Maybe they'll say that while the Saudis may fund mosques in Europe that are so radical refugees from the Middle East are afraid to attend them, they will keep the price of oil low and cripple Russia if we ask nicely.

If that is the case, it's a perfect opportunity for Trump to consider dramatically revising the terms of the special relationship between the United States and Saudi Arabia. Make a deal, Mr. Trump.