SOMERVILLE — In April I asked Sen. Angus King for his opinion about U.S. support for the Saudi-led air war against Houthi rebels in Yemen, the poorest country in the Middle East. He said, “I think it’s a mistake … I think we should have a review of our current policy. Because we can’t be complicit. We can’t avoid our responsibility by saying that we don’t know where that jet fuel went.”

The senator is exactly right. Both sides are guilty of grave human rights violations in the Yemeni civil war, which began when the Houthis ousted the elected president in October 2014.

But the Saudi-led air force coalition has devastated civilian infrastructure with American-made bombs and aerial refueling by the U.S. military. Food shipments have been disrupted, water systems bombed out of operation and the medical system pushed near collapse. As a result, 7 million Yemenis are on the edge of starvation, 17 million are in dire need of humanitarian assistance, and thousands are dying every month from preventable diseases like cholera.

In June, King voted with 48 other senators to block further sales of U.S. smart bombs to the Saudis, but 52 of his colleagues voted to let the sales go through.

And the Saudi-led coalition continued its strikes on civilians, including one this month that killed 20 fleeing villagers. Most were from a single family.

King was right to connect American moral complicity with “jet fuel.” Our government has pumped 67 million pounds of the stuff into coalition jets, literally fueling 9,000 bombing runs. Yet the lack of accountability and oversight for this assistance is shocking.

In three years of war, Washington has suspended the refueling assistance only once, after the Saudis bombed a funeral home in the Yemeni capital of Sana’a, killing at least 140 people. But nothing changed. The Saudis continued their deadly attacks, and the fuel was turned back on two months later. In 2017, the monthly average of fuel assistance is a third higher than in 2015 or 2016.

The Pentagon collects information about civilian casualties in wars we are directly engaged in. But since the U.S. has not declared war on the Houthi rebels, there is no official data available on the human consequences of our 67 million pounds of jet fuel. When journalists asked a U.S. military spokesman about this, he answered, “They request refueling and we provide it. I will refer you to the Saudi-led coalition as to the reasons why they requested the amounts of fuel.”

In other words, U.S. support for the Saudis is on auto-pilot, with no effective civilian or military oversight.

But thanks to Yemeni and international activists and journalists, we do “know what that jet fuel was used for.”

For example, the Yemen Data Project has painstakingly cross-checked the targets of all coalition air strikes using publicly available information and queries to both sides of the conflict.

Their results indicate that at least one third of these bombings were aimed at civilian targets like markets, private homes, schools and hospitals.

The Mwatama Organization for Human Rights, Amnesty International, Human Rights Watch and other groups have provided detailed descriptions of many of the worst bombings. The directors of the International Red Cross and Norwegian Refugee Council, two of the world’s largest humanitarian responders, describe in horrifying detail the hospitals full of starving children that have resulted from the coalition’s ceaseless attacks on civilian infrastructure.

Angus King has exhibited great thoughtfulness and nuance in his public statements about Yemen and in his voting record.

But the time for thoughtful consideration has passed.

It is time for moral leadership. As a veteran member of the Senate Armed Services Committee, King can introduce legislation to end American complicity in Yemen’s destruction.

The House recently passed amendments to the National Defense Authorization Act that would prohibit sending U.S. troops to fight in the Yemeni civil war, and to require reports on the Saudi coalition’s record of protecting civilians and the role of U.S. military personnel in the coalition war effort.

But King should go further, and call for an end to the unaccountable, immoral refueling program that makes Saudi airstrikes on civilian targets possible.

Another year of monitoring and deliberation will only confirm what journalists and human rights activists have reported since 2015: America is enabling an atrocity against the people of Yemen.

Angus King knows that we must not be complicit. Now he must act.