WASHINGTON ― After months of global controversy over Saudi Arabia for its role in the devastation in Yemen and the murder of Jamal Khashoggi, Congress could issue the longtime American partner’s biggest U.S. rebuke this week ― if a handful of senators agree.

The Senate will soon vote on a bill from Sens. Bernie Sanders (I-Vt.), Chris Murphy (D-Conn.) and Mike Lee (R-Utah) that would end American support for a Saudi-led military campaign in Yemen that has killed thousands of civilians and pushed millions to the brink of starvation. Sanders and his allies already introduced the legislation earlier this year, only to see it shelved in favor of a different bill that allowed the Trump administration to continue the assistance as long as it offered certifications the Saudis were trying to help civilians and work toward peace.

Now a new vote is expected to take place on Wednesday afternoon or Thursday ― and the bill has gained the public support of the top Senate Democrats on foreign policy and military affairs, Sens. Bob Menendez (N.J.) and Jack Reed (R.I.), while anti-Saudi sentiment among lawmakers has grown because of the kingdom’s role in Khashoggi’s killing and widespread disdain for the assurances that Trump officials provided.

The goal, congressional staffers and activists say, is to get at least 51 senators to vote to consider the legislation (if they only get 50, Vice President Mike Pence could join their opponents in a tie-breaking vote). Forty-four senators voted in favor of considering it back in March.

Most Democrats are considered safe bets, but the bill’s proponents need to sway at least five, and ideally more, of those who in March voted with most Republicans and have not yet made their positions clear: Sens. Chris Coons (Del.), Catherine Cortez Masto (Nev.), Joe Donnelly (Ind.), Heidi Heitkamp (N.D.), Joe Manchin (W.V.), Doug Jones (Ala.), Bill Nelson (Fla.), and Sheldon Whitehouse (R.I.).

They also need to retain at least some Republican votes. Lee and Sen. Rand Paul (R-Ky.) are expected to hold firm, but the others who voted with them in the spring ― Sens. Susan Collins (Maine), Jerry Moran (Kansas) and Steve Daines (Mont.) ― may not. Still, advocates of the bill are hopeful about other Republicans concerned with Saudi misconduct: Sens. Todd Young (Ind.), James Lankford (Okla.), Joni Ernst (Iowa) and Marco Rubio (Fla.).

“Our arguments have only strengthened,” said Kate Gould of the Friends Committee on National Legislation, one of scores of groups lobbying Congress in support of the bill.

She pointed to bipartisan public criticism of Trump aides’ claims that Saudi behavior has improved and the administration’s recent decision to end one of the biggest elements of American assistance to the Yemen campaign, the aerial refueling of planes flown by the Saudis and their ally the United Arab Emirates.

That sudden move undercut years of U.S. government arguments to Congress and the public ― begun under President Barack Obama ― that American support was key to keeping the Saudi-led coalition from committing war crimes or being overwhelmed by Iran-backed rebels. The arbitrary way the Trump administration decided to end refueling should show senators it’s important to codify the no-refueling policy, Gould argued, lest President Donald Trump restart it. Earlier this year, Trump actually wanted to expand support for the Saudis, to whom he has grown close.

[Saudi leadership’s] role in the murder of Jamal Khashoggi has been a gamechanger in that it showed some of the Saudi government’s most virulent supporters that it is willing to lie to their faces about its actions. Kate Kizer, Win Without War

Still, nailing down the bill’s prospects remained difficult less than 24 hours before lawmakers would have to reach a final decision ― a testament to the way Congress has tried to avoid hard and potentially politically costly decisions on war and peace for years.

Spokespeople for the biggest lobbying targets ― Young, Jones, Cortez Masto, Donnelly, Heitkamp, Nelson, Moran and Ernst ― did not respond to HuffPost’s requests for comment.

“I’m inclined to support it,” Coons told HuffPost. Unlike Menendez and Reed, however, he has not publicly committed to doing so.

Many senators are likely holding off on a final comment until after they receive a classified briefing in defense of the policy from Secretary of Defense Jim Mattis and Secretary of State Mike Pompeo on Wednesday morning.

The tactic is likely to help opponents of the bill, like Senate Majority Leader Mitch McConnell (R-Ky.) ― but that the measure has to be taken at all is a signal of how worried they are they could lose the vote. The briefing has itself sparked controversy because senators wanted it to include CIA director Gina Haspel, whom they want to press on U.S. intelligence about the Saudi regime’s role in killing Khashoggi. The White House blocked her from taking part in the session.

Still, it’s one of the maneuvers available to McConnell, Trump and others who want to sustain U.S.-Saudi cooperation in Yemen. McConnell could also attempt to strip privileged status from the resolution, as his counterpart in the House, Speaker Paul Ryan (R-Wis.) recently did to a companion bill there, removing the requirement that the full Senate consider it and setting up what Coons called “a vote-a-rama” that would distract from the central issue. Behind-the-scenes pressure from the president or those close to him could have a particular influence on wavering Republicans, while lawmakers might try to avoid the vote by saying they are instead endorsing another recently introduced bill targeting the U.S.-Saudi relationship.

Outside groups pushing the Sanders-Lee-Murphy proposal say senators already know enough to make a decision. “The situation is significantly different now than in March: the humanitarian crisis is much more dire…[and the Saudi leadership’s] role in the murder of Jamal Khashoggi has been a gamechanger in that it showed some of the Saudi government’s most virulent supporters that it is willing to lie to their faces about its actions,” said Kate Kizer of the peace movement Win Without War.

Many lawmakers deeply involved in foreign policy who were previously relatively deferential to the Saudis, like Rubio and Sen. Bob Corker (R-Tenn.), have become increasingly outspoken against the kingdom since the journalist’s murder.

There’s also particular curiosity about senators who were voted out of office in the midterms ― like Donnelly, Heitkamp and Nelson ― who no longer have to worry about being painted as too anti-Trump or anti-military in an election cycle. They could be more motivated to vote their conscience and therefore support the bill, or they might be worried about a strong position affecting their future employment or political chances, Gould said.

But regardless of senators’ status, it’s increasingly hard to argue that the question of the U.S.-Saudi relationship does not deserve a thorough debate, advocates of the bill say. It will likely never become law since Trump would probably veto it, they say, but its importance is much greater.

“It sends a chill to the entire Saudi dictatorship, not only in terms of prosecuting the war in Yemen but also its own human rights abuses,” Gould said. “Ultimately, good relations with the U.S. depends on the relationship with Congress.”

Igor Bobic contributed reporting.