As debate continues to rage over the Israel Anti-Boycott Act, and one rumored 2020 presidential candidate distances herself from it, another prominent Democrat and rumored presidential candidate has come out against it as well. Senator Elizabeth Warren announced her opposition to the bill this week, calling it a violation of free speech.

Warren, who was never a sponsor of the bill, was asked about it by a constituent at a town hall last night. In response, she said that while she disagreed with BDS, she also said that "outlawing free speech-protected activity violates our basic constitution."

The bill is an addition to the Export Act of 1979, which criminalized a company knowingly joining the Arab League boycott of Israel. This addition would update the bill to criminalize US companies from joining on to boycotts of US allies called for by intergovernmental organizations such as the United Nations or the European Union. Violations could be punishable by up to $1 million in fines and 20 years in prison.

Besides Warren, other Democratic Senators are feeling the heat regarding the bill as well. Senator Ron Wyden of Oregon was confronted by constituents this past weekend who questioned why he supported the bill. Wyden argues that the bill simply updates the previous 1979 law targeting the Arab League boycott of Israel, and that no one has been imprisoned for violating that.

While supporters of the law like Wyden and Chuck Schumer claim that the bill doesn't infringe on free speech, a critic of the bill suggests that it still does, even if it doesn't punish individuals participating in the Boycott, Divestment and Sanctions movement.

Writing in the Jewish Telegraphic Agency, legal scholar David Schraub notes that although the bill would criminalize companies for agreeing to engage in what is now a hypothetical boycott of Israel by the EU or UN, it would still be legal to join the BDS movement at the compulsion of a group that isn't an intergovernmental organization.

But the free speech threats still exist, according to Schraub, because "whether or not Israel boycotters are doing so because they personally find the nation terrible versus because they wish to 'support' a U.N. declaration that Israel is terrible will often be quite blurry."

While Gillibrand has been the only senator to drop her co-sponsorship of the bill, the bill has picked up three more co-sponsors since she came out against it: Republican Senators Steve Daines, Jeff Flake and Richard Shelby.