“We strongly support this legislation, which contains pro-Israel provisions that have previously gained wide bipartisan support — and we urge the Senate to move as quickly as possible to adopt it,” AIPAC spokesman Marshall Wittman told Jewish Insider in an email today.

Timing the vote in the middle of a partial government shutdown has forced the historically nonpartisan, pro-Israel group American Israel Public Affairs Committee (AIPAC) to make one of its most partisan legislative pushes yet.

All four provisions in Rubio’s package enjoyed significant bipartisan support in the previous Congress. Yet Democrats have refused to move forward with any legislation until Congress passes spending legislation to reopen the government, which has stalled amid disagreements over funding for President Donald Trump’s proposed wall on the US-Mexico border.

The Senate failed 56-44 to reach the 60-vote threshold needed to clear a procedural hurdle on the Strengthening America’s Security in the Middle East Act, introduced by Sen. Marco Rubio, R-Fla. Rubio’s legislation consists of four Middle East-related bills that had been held up in the last Congress, including a provision taking aim at the pro-Palestinian boycott, divestment and sanctions (BDS) movement.

Republicans’ very first bill in the new Senate is highlighting divisions among Democrats over boycotts of Israel and its West Bank settlements while drawing the traditionally nonpartisan pro-Israel lobby further into a partisan political quagmire.

AIPAC openly stepped into partisan politics during its advocacy against President Barack Obama’s Iran nuclear deal. That deal was opposed by 23 Democrats, including some in leadership. Only four Democrats voted for today’s bill: Doug Jones, Joe Manchin, Kyrsten Sinema and Bob Menendez. (Senate Majority Leader Mitch McConnell, R-Ky, changed his vote to a "no" after the final tally to preserve his ability to bring the bill back to a vote.)

“This is the part of the broader effort to weaponize Israel,” Lara Friedman, the president of the Foundation for Middle East Peace, a nonprofit opposing Israeli settlements in the West Bank, told Al-Monitor. “So long as progressives let [Prime Minister Benjamin Netanyahu], AIPAC and the Republican Jewish Coalition define them as pro-Israel, they’re going to get kicked in the stomach.”

Indeed, the bill has allowed Republicans to draw out the Democratic caucus’ stinging divisions on the Israeli-Palestinian conflict and anti-boycott legislation.

At issue is the AIPAC-backed Combating BDS act, which Senate Minority Leader Chuck Schumer, D-N.Y., himself co-sponsored in the last congress. Before Rubio wrapped it into today’s bill, it had 48 bipartisan co-sponsors.

The legislation gives cover to state-level laws designed to clamp down on boycotts of Israel or its West Bank settlements. The American Civil Liberties Union (ACLU) opposes the bill on the grounds that it encourages states to pass laws violating constitutionally protected free speech rights.

The Senate bill also includes the US-Israel Security Assistance Authorization Act, which would codify the 10-year, $38 million military aid package with Israel into law. It also contains a Syria sanctions bill and a bill that would extend expedited military assistance for Jordan.

But it’s the Combating BDS Act that has proven to be most divisive among Democrats. Adding it to an otherwise noncontroversial legislative package has allowed Republicans to exploit those divisions this week as lawmakers assailed one another over Twitter.

The online drama reached its peak Monday when Rubio said on Twitter, “The shutdown is not the reason Senate Democrats don’t want to move to Middle East security bill.” Rubio alleged that a “significant” number of Senate Democrats came out in favor of BDS at a Democratic caucus meeting last week as they discussed his bill.

“I hope a staffer wrote this tweet and when you see it you take it down,” Sen. Chris Murphy, D-Conn., countered on Twitter.

“You know it isn’t true,” said Murphy, adding that it’s “really dangerous to play politics [with] support for Israel.”

Neither Rubio’s nor Schumer’s office replied to Al-Monitor’s request for comment on the meeting. No senator in either party has publicly endorsed the BDS movement.

That’s not the case in the House, where two new members — Reps. Rashida Tlaib, D-Mich., and Ilhan Omar, D-Minn. — have embraced boycotts.

Tlaib, the first Palestinian American woman in Congress, caused a stir by tweeting that supporters of the Senate bill “forgot what country they represent. This is the US where boycotting is a right & part of our historical fight for freedom & equality. Maybe a refresher on our US constitution is in order, then get back to opening up our government instead of taking our rights away.”

Rubio immediately hit back, tweeting, “This ‘dual loyalty’ canard is a typical anti-Semitic line. BDS isn’t about freedom & equality, it’s about destroying Israel.”

The Jewish Democratic Council of America also criticized Tlaib, tweeting, “We oppose your charge of dual loyalty. It’s wrong, dangerous and hurts the cause of peace.”

The heated online exchange began when Sen. Bernie Sanders, I-Vt., echoed arguments from the ACLU, which does not take a position on BDS itself despite its opposition to the Senate bill on constitutional grounds.

“It’s absurd that the first bill during the shutdown is legislation which punishes Americans who exercise their constitutional right to engage in political activity,” Sanders tweeted.

Sanders, a prospective 2020 presidential candidate, joined Sen. Dianne Feinstein, D-Calif., in urging the Senate to refrain from attaching a similar anti-boycott bill to spending legislation late last year.

“While we do not support [BDS], we remain resolved to our constitutional oath to defend the right of every American to express their views peacefully without fear of or actual punishment by the government,” Sanders and Feinstein wrote in a letter to Schumer and Majority Leader Mitch McConnell, R-Ky.

The letter was a rebuke to fellow Democrat Sen. Ben Cardin, D-Md., who had urged leadership to attach his AIPAC-pushed Israel Anti-Boycott Act to spending legislation before the shutdown began. Cardin’s bill would fine US companies and their employees for complying with internationally organized boycotts of Israel.

Still, Rubio maintains that Sanders’ and Feinstein’s position is tantamount to supporting BDS.

“Many claim they oppose BDS,” Rubio tweeted today. “But shielding BDS from counter-boycotts is de facto support of BDS.”