WASHINGTON — Senate Democrats failed to advance a bipartisan border security bill Thursday, with nearly every Republican voting to filibuster it as Donald Trump wields border chaos as a centerpiece of his 2024 campaign against President Joe Biden.

The vote was 43-50, falling short of the 60 needed to proceed. Republican Sen. Lisa Murkowski of Alaska was the only GOP senator to vote to advance the bill Thursday, while six Democrats voted with the remaining Republican senators to block it.

The vote caps a peculiar sequence of events after Senate Republican leaders insisted on a border security agreement last year and signed off on a compromise bill before knifing it. Democrats, wary of their political vulnerability when it comes to migration, had acceded to a variety of GOP demands to raise the bar for asylum seekers and tighten border controls. Trump pressured GOP lawmakers to kill any deal that wasn’t “perfect” and succeeded.

The vote, while expected to end in failure, was brought up to put Republicans on record in opposition to the bipartisan compromise and as an opportunity for politically endangered Democrats to try and demonstrate they’re willing to get tough on immigration.

“This commonsense bill would push back on the Biden Administration’s failed border policies by forcing the President to shut down the border, strengthen our asylum laws, and end catch and release. It is shameful that Mitch McConnell and D.C. politicians would rather keep the border as a political talking point than actually fix the problem,” Sen. Jon Tester, D-Mont., who faces a difficult re-election battle in a red state, said in a statement.

His fellow Montanan, Republican Sen. Steve Daines, is the chair of the campaign arm seeking to capture the Senate majority for the GOP this fall by defeating Tester and others. Daines called the vote a “political stunt” by Democrats.

The legislation was negotiated by James Lankford, R-Okla., who was designated by Senate Minority Leader Mitch McConnell, R-Ky., to lead the talks. He cut a deal with Sens. Chris Murphy, D-Conn., and Kyrsten Sinema, I-Ariz., that McConnell and Senate Majority Leader Chuck Schumer, D-N.Y., signed off on. But Republicans immediately came out against it, causing McConnell to change his position. Initially, the border provisions were set to be attached to funding for Ukraine and Israel, but Congress passed those aid measures separately.

The Biden-backed compromise bill was crafted to reduce border crossings, raise the standard for migrants to qualify for asylum and empower officials to rapidly send away those who fail to meet that standard. It would give the president power to shut down the border if migration levels exceed certain thresholds. On the brink of its release earlier this year, Lankford told NBC News it was “by far the most conservative border security bill in four decades.”

He voted against it Thursday, as did Sinema, with the Republican calling it a stunt vote.

Lankford said the chances of getting a border security solution are “pretty slim” this year. “At this point, no one really seems to want to have serious conversation on it,” he said.

Even if it passed the Senate, GOP leaders have made clear that the bill would be dead on arrival in the House.

Sen. Ted Cruz, R-Texas, who faces re-election this fall, claimed that the border security bill was “designed to fail.”

“In fact, we can quantify mathematically the chances this bill has a passing the House of Representatives. And those chances are 0.00%,” Cruz said on the Senate floor. “Instead the Democrats deliberately want this border crisis to continue.”

Speaker Mike Johnson, R-La., said Thursday that Congress should pass the GOP’s more aggressive immigration bill, known as H.R.2., which was crafted on a partisan basis and lacks Democratic buy-in.

“It would reinstate Remain in Mexico, which was the policy that President Trump used to get control of this border. It would end the catch and release program,” Johnson said on Fox News. “It would fix the asylum— the broken asylum process and fix the parole process. You do those things, you solve the crisis, and the White House has no interest in doing that.”

House Minority Leader Hakeem Jeffries, D-N.Y., criticized Republicans for trying to “weaponize the issue politically” rather than fix the problems at the border.

“Extreme MAGA Republicans are not serious about addressing the challenges that clearly exist at the border, which is why they detonated their own legislation,” he said. “Democrats are going to continue to be reasonable, responsible and results-oriented. … Unfortunately, the Republicans appear as though they want to continue the meaning to chaos, dysfunction, and extremism. And if that keeps up, I think they will pay a price in November.”