The lead author of the controversial Israel Anti-Boycott Act, Democratic Sen. Ben Cardin of Maryland, is open to amending the legislation to address concerns raised by the American Civil Liberties Union, he told The Intercept Monday evening.

The ACLU warned last week that the measure, which targets the BDS movement, was unconstitutional and would have a chilling effect on free speech. In the wake of that warning, and a subsequent article by The Intercept, co-sponsors of the bill have begun to re-examine their support for it.

Cardin said that the ACLU had misinterpreted his legislation, but if it needed to be clarified, he would take the steps to do so. “A lot of the co-sponsors are pretty strongly committed to the freedom of speech,” Cardin said. “We’re certainly sensitive to the issues they raise. If we have to make it clearer, we’ll make it clearer.”

He and the ACLU, he said, disagreed about what the bill would do. “I respect greatly the ACLU. I think that many of their points are just not correct. We don’t want to do anything to infringe freedom of speech,” he said.

One issue of contention is whether criminal penalties such as a 20-year prison sentence would apply to those who violate the law. “I actually read it. Turns out, all of this is wrong,” offered the legal affairs correspondent for the Daily Beast in his hot take on the bill. “The ACLU misread the law.”

On Monday night, in an op-ed in the Washington Post, two top officials at the ACLU stood by their legal interpretation. “Violations would be punishable by civil and criminal penalties of up to $1 million and 20 years in prison,” write David Cole and Faiz Shakir, the ACLU’s legal and political directors, respectively.

“We thought we only dealt with civil penalties, not criminal penalties,” Cardin told The Intercept. “But if that’s not clear, we’re willing to deal with these issues.”

If the bill were amended to clarify that no criminal penalties could be applied, violators would still face a $250,000 civil fine or more.

Cardin also said that individual American citizens who backed a boycott of Israel would face no legal consequences, and made that point in a letter penned with co-sponsor Sen. Rob Portman, R-Ohio, which was sent to colleagues on Friday.

But the text of the bill bans actions “which have the effect of furthering or supporting restrictive trade practices or boycotts fostered or imposed by any international governmental organization against Israel or requests to impose restrictive trade practices or boycotts by any international governmental organization against Israel.”

It’s not hard to see how the ACLU read that as a broad ban that criminalized speech.

Co-sponsors of the bill have faced pressure at home to explain support for a bill with such language in it. Rep. Joe Kennedy III, D-Mass., is reviewing the bill in the light of the ACLU’s concerns, as are Democratic Sens. Kirsten Gillibrand of New York, Maria Cantwell of Washington, Ron Wyden of Oregon, Claire McCaskill of Missouri, and Richard Blumenthal of Connecticut.

Gillibrand was pressed on her support for the measure at a town hall in New York over the weekend, and said that she was reviewing it in the wake of the ACLU letter. She added criticism of Israeli leader Benjamin Netanyahu, whom she said had no vision for peace in the region. “I do share your concerns about the current government of Israel,” she told an activist with Jewish Voices for Peace. (The group said on Monday that five of its activists were barred from traveling to Israel at an American airport; supporting BDS in Israel is a civil offense.)