The first Twitter war involving sitting lawmakers in the early days of the 116th Congress wasn’t over immigration, “the Wall,” or even Russiagate. It may come as a surprise that the opening rhetorical shot was over an international protest movement targeting Israel’s treatment of Palestinians in the West Bank and Gaza, otherwise known as BDS (Boycott, Divestment, Sanctions).

On January 3, amid the seemingly intractable government shutdown, Senator Marco Rubio made it his first order of business to sponsor a bill that supports the punishment of any U.S. company or contractor who engages in BDS by refusing to work with Israel. When Michigan Representative Rashida Tlaib chided Rubio in a tweet, saying, “they forgot what country they represent,” and that “maybe a refresher on our U.S. Constitution is in order,” Rubio promptly shot back.

“This ‘dual loyalty’ canard is a typical anti-Semitic line,” the Florida senator tweeted. “#BDS isn’t about freedom & equality, it’s about destroying #Israel.”

Tlaib, newly inaugurated as the country’s first Muslim female congresswoman (along with Minnesota Representative Ilhan Omar) returned fire, underscoring that “it’s clear my earlier tweet was critical of U.S. Senators like yourself, who are seeking to strip Americans of their Constitutional right to free speech.”

[Editor’s Note: Since this article went to print, Omar has been asked by Democratic leaders to apologize twice for “anti-Semitic” comments she made regarding AIPAC’s influence on Congressional legislation and members’ support for Israel]

It was game on from there. The spat was a skirmish in a much larger war that is being waged by Israel and its supporters across the country against BDS, and may expose one of the biggest fault lines in the Democratic Party today—that of the traditionally pro-Israel Left squaring off against a growing number of progressives who not only sympathize with the Palestinian cause, but don’t truck with the idea of having their ability to engage in political boycotts denied by the government.

That latter group, which includes liberal heavyweights Senators Bernie Sanders (I-Vt.) and Dianne Feinstein (D-Calif.), is finding common cause with other civil libertarians across the political spectrum, including Republican Senator Rand Paul, who penned an op-ed for The American Conservative in January. In it, he said he did not personally support BDS, but recognized that the freedom to boycott is the bedrock of American civic life, from the Boston Tea Party to the Rosa Parks-inspired bus protests in Montgomery, Alabama, which took place over 381 days in 1955 and 1956. “By all means, opponents of boycotting Israel should be heard—but so should their opponents,” Paul wrote. “Legislation to end boycotts goes against the very principles America was founded upon.”

Sanders was much more blunt in his response to Rubio. “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,” he tweeted on January 7.

Rubio, not exactly known for his elegant ripostes, suggested the government itself has free speech, tweeting, “So boycotting #Israel is a constitutional right, but boycotting those participating in #BDS isn’t?” He also needled Senate Democrats by suggesting that a “significant” number of them support the boycotts. It’s a testament to how radioactive this issue is that his charge drew such swift rebuke from Democrat Senator Chris Murphy of Connecticut, who demanded a retraction.

Rubio’s bill, after all the attending drama, passed the Senate by a vote of 77 to 23 on February 5. Of course his anti-BDS “Strengthening America’s Security in the Middle East” package also included $38 billion in aid to Israel over 10 years, additional sanctions against the Bashar al-Assad government in Syria, aid to Jordan, and a controversial last-minute amendment by Senate Majority Leader Mitch McConnell, admonishing President Donald Trump for pursuing a “precipitous” military withdrawal from Syria and Afghanistan. The only Republican “nay” vote was Paul. Several Democratic presidential hopefuls voted against it as well, including Senators Kamala Harris (D-Calif.), Cory Booker (D-N.J.), Kirsten Gillibrand (D-N.Y.) and Elizabeth Warren (D-Mass.)

A House version of the bill faces a more uncertain future, with majority Democrats, so far, appearing less inclined to bring it to a vote. An anti-BDS bill would certainly divide the ranks publicly—a scene Speaker of the House Nancy Pelosi would be loathe to encourage in her first few months back on the job.

Rubio’s is the weakest of all the proposed anti-boycott bills to come down the congressional pike, however, in that it merely gives cover to state and local governments that want to punish entities that engage in the anti-Israel protest. As of January, 26 states now have measures that require them to deny contracts to and divest from any companies that are involved in BDS.

One of the highest-profile cases to date is Bahia Amawi, a child language specialist who was contracted to work in the Texas public school system for nine years until December, when she was fired for refusing to sign a pledge not to boycott Israel. (When Texas Governor Greg Abbott signed his state’s anti-BDS bill in May 2017, he said he was “proud to have commemorated Israel’s Independence Day.”) As journalist Glenn Greenwald pointed out, if she had signed, Amawi would not only be prevented from boycotting goods sold by companies in Israel and the occupied West Bank, but she would be barred “even from advocating such a boycott given that such speech could be seen as ‘intended to penalize, inflict economic harm on, or limit commercial relations with Israel.’”

There were no other requirements in her contract pertaining to political speech. Therefore, she would in theory be free to engage in all sorts of protests against her own country, or any other government in the world, except Israel. The American Civil Liberties Union has filed a lawsuit against the state on behalf of Amawi, alleging the contract violated her right to free speech. They also filed suit on behalf of four more Texans before Christmas, including a public radio station reporter who signed the pledge against his personal beliefs just to keep his job.

Rubio’s bill proposes that the “sense of Congress” is to support the states that pass these kinds of measures, and that no existing federal law would preempt them. He is four square with the pro-Israel lobby, including the American Israel Public Affairs Committee (AIPAC), as it ramps up a multi-front campaign to destroy BDS everywhere in the U.S., including college campuses and in state and federal government. And he isn’t the only one. When Representatives Tlaib and Omar became the first members of Congress to openly support BDS, Senator Cory Gardner (R-Colo.)—who is widely believed to be one of the most vulnerable senators in 2020—spearheaded a letter to the Senate leadership “condemning BDS” and supporting federal legislation against it. The letter was signed by an additional 14 Republican senators, including Chuck Grassley, Lindsey Graham, and another vulnerable Republican, Susan Collins.

According to a 2018 Pew Research Center report, the number of Republicans that sympathize with Israel over Palestine has increased to 79 percent, while sympathy for Israel dropped among Democrats to 27 percent, a disturbing trend especially for the anti-BDS movement. Besides growing sympathy for the Palestinians, progressives are echoing the ACLU and other groups who say any law prohibiting boycotts won’t ultimately survive a Supreme Court test.

They are probably right. In NAACP v. Claiborne Hardware Co. (1982), which involved a boycott on white merchants by black community members and organizations in Claiborne County, Mississippi, in 1966, the Supreme Court explicitly held that the First Amendment protects the right to boycott. Two federal courts relied on this precedent in overturning anti-BDS laws in two states last year.

In Kansas, a federal judge ruled in January 2018 that a state law requiring any contractor seeking business with the state must “certify that they are not engaged in a boycott of Israel,” was a direct infringement of the First Amendment. That suit was brought by the ACLU on behalf of Esther Koontz, a Mennonite who personally (and as part of her church’s boycott) refuses to buy goods made in Israel. She lost out on a teaching job with the state because she would not certify otherwise. Kansas has since amended the law to apply only to businesses with contracts of more than $100,000—but the ACLU says it is still unconstitutional. Remember Citizens United and Hobby Lobby? In both cases, the Supreme Court afforded corporations constitutional protections.

In Arizona, a federal judge specifically recognized the First Amendment rights of companies doing business with the state when in September she ruled in favor of Mikkel Jordahl, who runs a one-man law firm in Sedona. “A restriction of one’s ability to participate in collective calls to oppose Israel unquestionably burdens the protected expression of companies wishing to engage in such a boycott,” Judge Diane Humetewa wrote in her opinion for Jordahl et al v. Brnovich et al.

This of course has not stopped other states from pursuing their own versions of the law. Democratic Governor Andrew Cuomo reportedly has a blacklist of companies that the state will not work with because they violate the anti-BDS executive order he issued in 2016. Maryland’s Republican Governor Larry Hogan signed his own executive order banning boycotters from state contracts in October 2017. When asked about the constitutional concerns, Hogan dismissed them outright.

“They’re asking [companies and individuals] to discriminate against Israel,” Hogan said of BDS. “There’s no argument to the contrary that makes any sense.” Alan Ronkin, a regional director for the American Jewish Committee (AJC), on hand for the signing, insisted that people are free to say whatever they want about Israel, but “the state is free to do business with companies that reflect its values.” (AJC is a fierce BDS critic that for years has argued that “anti-Zionism is a form of anti-Semitism.”)

Syed Saqib Ali, a former Maryland state delegate, doubts that is how the Constitution works. He is suing the state because he says Hogan’s edict “chills constitutionally protected political advocacy,” and is preventing him from getting a job with the state.

“To even apply for that job, I have to give up my free speech rights,” Ali told a reporter in January. “I will not tolerate that.”

Maryland’s senior Senator Ben Cardin, a Democrat, along with Senator Rob Portman, (R-Ohio), has been trying to pass his own federal anti-BDS legislation for some time now. Their proposal targets individuals, not just companies, so it could be much more dangerous. They even tried, unsuccessfully, to sneak it into the package of spending bills aiming to avoid the shutdown in December. The Israel Anti-Boycott Act focuses on expanding the 1979 Export Administration Act to prohibit any U.S. person involved in “interstate or foreign commerce” from engaging in “any boycott fostered or imposed by any international governmental organization against Israel.”

The bill suggests that a non-binding 2016 United Nations Human Rights Council resolution supporting BDS stands in for the offending “international governmental organization.” From there it wouldn’t be difficult to see how this law could affect anyone remotely involved in the boycott. An earlier iteration involved prison time for violators. The sponsors have since softened it with an amendment, taking away jail time but imposing financial fines. But adding that nothing in their bill “shall be construed to diminish or infringe upon any right protected under the First Amendment,” doesn’t necessarily make it so.

So why all the energy to have it fail in court? Critics believe that most of these efforts are largely designed to intimidate. On the college level, a recent investigative series by The Forward magazine shed light on a massive online blacklist called canarymission.org. Its motto is, “if you’re racist, the world should know.” Many of the outed “racists” and “anti-Semites” on the site are students and professors who have merely questioned Israeli policies and supported BDS, and are now forced to scrub their reputations. According to reporter Josh Nathan-Kazis, this is one flank in a much greater, well-coordinated rapid response force involving groups ranging from AIPAC to the David Horowitz Freedom Center that fly into action at the whiff of a protest or student government resolution on campus.

“The total amount of American Jewish and Israeli government funds flooding the anti-BDS effort is easily in the tens of millions of dollars each year,” Nathan-Kazis wrote in August.

If that’s ground zero, then what’s happening on Capitol Hill is the final destination, the promise of a blanket federal edict that would stop all boycotts—no matter where they are—in their tracks. The success of this unprecedented effort to control speech partly depends on Democrats continuing to divide on this issue, and whether Tlaib and Omar are early harbingers, signaling a brave new civil libertarian stand on the issue—or not.

Kelley Beaucar Vlahos is Executive Editor of The American Conservative. Follow her on Twitter @Vlahos_at_TAC