WASHINGTON – In a historic bipartisan rebuke of the president and a marked shift in the long-standing U.S. alliance with Saudi Arabia, the Senate voted Thursday to try to force the Trump administration to end its military support for the Saudi-led war in Yemen.

Although the measure will stall in the House for now, the Senate's 56-41 vote carried extraordinary significance – marking the first time the Senate has invoked Congress' war powers to challenge U.S. military involvement abroad. The step was both a condemnation of Saudi Arabia's execution of the Yemen war – which has killed thousands of civilians and created a humanitarian catastrophe – and of the kingdom's role in the murder of Jamal Khashoggi.

“Today, we tell the despotic regime in Saudi Arabia that we will not be a part of their military adventurism,” said Sen. Bernie Sanders, I-Vt., who championed U.S. withdrawal from the Yemen conflict along with Sens. Chris Murphy, D-Conn., and Mike Lee, R-Utah. "The United States Congress ... is sick and tired of abdicating its constitutional responsibility on matters of war," Sanders said.

Senators unanimously approved a separate, nonbinding resolution naming Saudi Arabia's crown prince, Mohammed Bin Salman, as responsible for Khashoggi's death. The Washington Post columnist was killed inside the Saudi Consulate in Istanbul on Oct. 2 by a team of Saudi operatives, many of whom have been tied to the crown prince.

The resolution, introduced Thursday by Senate Foreign Relations Committee Chairman Bob Corker, R-Tenn., calls on the Saudi government “to ensure appropriate accountability for all those responsible for Jamal Khashoggi’s murder” and urges the kingdom to “moderate its increasingly erratic foreign policy,” among other steps.

"The United States Senate has said the Crown Prince Mohammed Bin Salman is responsible for the murder of Jamal Khashoggi," Corker said. "That is a strong statement. ... I think it speaks to the values that we hold dear."

The two Senate votes were a direct challenge to President Donald Trump, who downplayed evidence that Saudi Arabia's crown prince was involved in Khashoggi's murder and said the incident should not damage U.S.-Saudi relations. His administration, through his son and adviser Jared Kushner, has cultivated close ties to the kingdom.

"Today is a watershed moment for Congress," Murphy said. "We are reasserting our responsibility to be a co-equal branch with the executive (branch) in foreign policymaking."

It was also a watershed moment for Sanders, Murphy and Lee – an odd-bedfellows trio who have tried for three years to curb American support for the Saudi-led war in Yemen. Their first effort, on a measure that would have blocked arms sales to the Saudis in 2016, garnered only 27 "yes" votes.

Thursday, seven Republican senators joined all the chamber's Democrats and its two independents in passing the Yemen resolution, which would require the United States to stop providing intelligence, targeting assistance in bombing and other military support to the Saudi government and its allies in the Yemen conflict.

Before the Senate vote, House GOP leaders blocked a similar measure from coming up for a vote in that chamber. Proponents vowed to revive the issue when Democrats take power in January.

“We won’t ignore these issues in the next Congress,” said Rep. Eliot Engel, D-N.Y., who will become the new chair of the House Foreign Affairs Committee in January. “It’s a betrayal of the men and women who have served this country in uniform.”

Proponents of the Yemen resolution said America’s involvement in the war was unauthorized, unconstitutional and immoral. They argued that Congress has abdicated its responsibility for decades, fearing the responsibility that comes with sending American troops into harm's way.

"There is no decision that is more fraught with moral peril," Lee said at a news conference after the vote. "When we’re putting American treasure and, even more importantly, American blood on the line, it is wrong to entrust that to one person."

Sanders and others said they hoped the Senate’s action would bolster negotiations, led by a United Nations special envoy, to end the horrific conflict. Since hostilities began in 2015, the Yemen war has left thousands of civilians dead and created the world’s worst humanitarian disaster – putting millions on the verge of starvation.

Opponents of the resolution said U.S. support for the Saudi-led coalition did not amount to warfare, and they argued that U.S. involvement was vital to helping Saudi Arabia contain Iran's influence in the Middle East.

The war is a proxy battle between Saudi Arabia and Iran, two regimes vying for expanded influence in the region. The United States stopped refueling Saudi jets, but it still provides munitions and intelligence to the Saudi government.

"There is a threat in the Middle East posed by Iran and their ambitions which must be confronted," Sen. Marco Rubio, R-Fla., said during Thursday's Senate debate. Rubio suggested that the U.S.-Saudi alliance would be "shattered" if the United States ended its military role in Yemen, and the war would spiral further out of control.

Though lawmakers focused mostly on Yemen, they were spurred to act by Khashoggi’s murder. Proponents of the war resolution said his brutal killing, and the crown prince's alleged involvement, strengthened their case for withdrawing.

"The murder of Mr. Khashoggi caused us to think long and hard, with good reason, about the fact that we've got somewhat blindly into this war," Lee said in a floor speech Wednesday. "When we pulled back the curtains and we look into exactly who we're fighting for and why we're fighting, people understandably got a little freaked out."

Several lawmakers said Khashoggi's murder was part of a broader pattern of disturbing actions by the Saudi regime, led by the crown prince, who is Saudi Arabia’s de facto ruler. They cited the kidnapping of the Lebanese prime minister and the detention of many in the prince's own family, among other incidents.

Several top lawmakers said Thursday's Senate vote marked the beginning, not the end, of the debate over Khashoggi's murder – and by extension, the debate over America's long-standing alliance with Saudi Arabia.

"I’m never going to let this go until things change in Saudi Arabia," Sen. Lindsey Graham, R-S.C., said Wednesday. He is part of a bipartisan group of senators pressing for sanctions on any Saudis, including the crown prince, found responsible for Khashoggi's murder, and a suspension in U.S. arms sales to the kingdom.

"Do you really want to transfer your most advanced technology to somebody who thinks it’s OK to lure a journalist to a consulate in Turkey … and chop him up?" Graham said, referring to reports that Khashoggi was tortured and dismembered. "The crown prince is so toxic, so tainted, so flawed that I can’t ever see myself doing business with Saudi Arabia" unless there's a change in leadership.

Trump condemned Khashoggi's death but said the incident should not harm U.S.-Saudi relations. The administration relies heavily on Saudi Arabia in its effort to isolate Iran, and Trump championed U.S. arms sales to the regime as an economic boon.

Murphy and others said Trump's response to the Khashoggi killing has so infuriated lawmakers in both parties that it has spurred a fresh desire to debate and legislate on foreign policy. He said that sentiment will last well into the next Congress.

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