Advocates of boycotting Israel are under attack in a number of states across the country. State legislatures in California, New York, Indiana, Virginia, Pennsylvania and Florida are debating anti-boycott measures. Most of them would penalize people or businesses that support the boycott, divestment and sanctions (BDS) movement targeting Israel over human rights violations. Some of the bills would also hit those who only advocate for boycotting products made in Israeli settlements.

Supporters of the BDS movement are now mobilizing to try to defeat the bills–and in Maryland, activists say an anti-boycott bill a local Jewish group wanted to push for was defeated after the Freedom2Boycott coalition protested and lobbied against the measure. Some of the measures in other states have passed in the Assembly or Senate in a state, but have not yet been signed by the governors of the state.

The wave of anti-boycott bills is backed in some states by pro-Israel organizations. The measures are the latest line in a series of attacks the BDS movement has faced in state legislatures around the U.S. since 2014, when the American Studies Association passed a resolution in favor of boycotting Israel. Last year, twenty-two anti-BDS bills were introduced in U.S. legislatures. Lawyers warn that the measures may be unconstitutional and could chill speech that is critical of the state of Israel.

“BDS is gaining momentum, and that’s scaring a lot of people. That’s scaring a lot of Israel advocates,” said Rahul Saksena, an attorney at Palestine Legal, a group that fights back against attempts to curb speech in favor of Palestinian rights. Saksena said that instead of debating the movement, pro-Israel groups are trying to shut the movement down.

One of the most alarming bills is being debated in New York, which became the first state to consider anti-BDS bills in 2014, but not the first state to pass a measure. (In May 2015, South Carolina’s government became the first to pass legislation penalizing businesses that boycott countries South Carolina trades with. Boycotts of Israel were the clear target.)

The New York bills–there are two similar versions–would not only require the state to disinvest from companies that boycott Israel or products made in the occupied West Bank. It would also create a list of individual people and entities that boycott Israel, and post that list on the New York state website for the Office of General Services. It is the “most unconstitutional bill” being considered, said Saskena, though the others also raise constitutional issues. Advocating for boycotts is protected speech under the US Constitution.

One of the New York bills passed the state Senate in January by a 55-6 vote, and is now being debated in the Assembly. While that version applies to any boycotts of “allied nations,” the sponsor of the Assembly version of the bill only talked about the BDS movement when introducing it. The other version of the bill, which only mentions Israel, is being discussed in committee in the Assembly and the Senate.

Palestinian rights activists say the New York bill would create a “blacklist” reminiscent of the McCarthy era, when Hollywood shunned any writer, producer or actor allegedly associated with communism. And Josh Ruebner, policy director of the US Campaign to End the Occupation, told the Electronic Intifada he is worried that pro-boycott church groups who receive money from New York would see their funding slashed because of the bill. Palestine Legal’s Saskena said that Florida’s bill may also punish churches that have taken pro-Palestinian stands.

New York passed a resolution condemning BDS last year, but it had no teeth. The Jewish Community Relations Council advocated for the resolution, according to reporter Jacob Kornbluh, who writes on the Jewish community.

The other states– California, Indiana, and Florida–are considering bills that have similar language. They would prohibit their states from contracting with companies that boycott Israel. The Florida Senate and Indiana House have passed their measures, though they have to pass both the senate and house in these states to reach the governor. California is still debating the measure. The Virginia House passed a resolution condemning BDS for being “one of the main vehicles advocating for policies leading to the dissolution of Israel as a Jewish and democratic state.” Another Virginia bill directs the Virginia-Israel Advisory Board to examine how the BDS movement might impact businesses in the state and its ability to attract investment. Last year, a legislator in Pennsylvania introduced a bill to cut off funding to universities that boycott Israel–similar to a New York bill that was defeated in 2014.

But activists have successfully defeated anti-boycott bills in the past. Earlier this year, the Baltimore Jewish Council said they would push for a bill to prevent companies boycotting Israel from doing business with the Maryland state government. Now, activists in that state say they have quashed the prospect of that bill being introduced in the legislature.

“The Freedom2Boycott coalition has clearly had a huge impact in derailing the BJC’s plan to push an anti-BDS bill in Maryland. While the BJC announced that it will not pursue a bill, we are continuing to lobby representatives and monitor the legislature for any last-minute attempts to sneak a bill through as an amendment, which has been done before,” Alison Glick, a member of the Freedom2Boycott coalition and Jewish Voice for Peace, told me in an e-mail. “We will use our momentum to continue educating our legislators about what BDS really is and why it is important for achieving justice in Israel/Palestine.”

Correction: This article originally said the Maryland legislature considered an anti-BDS bill. It has not. Instead, the Baltimore Jewish Council said they wanted the bill to be introduced in the legislature. Activists say they lobbied against the measure being introduced–and were successful in their lobbying.