(JTA) — The American Civil Liberties Union filed a federal lawsuit challenging a Kansas law banning state business with companies that support the Boycott, Divestment and Sanctions movement, or BDS, against Israel.

The ACLU said Wednesday it was representing a public school math teacher who was denied a state contract because she participates in the anti-Israel boycott.

The law, which took effect on July 1, requires that any person or company that contracts with the state submit a written certification that they are “not currently engaged in a boycott of Israel.” The ACLU said that requiring teacher Esther Koontz to certify that she won’t boycott Israel violates her First Amendment rights.

“The First Amendment prohibits the government from using its financial leverage to impose an ideological litmus test,” ACLU attorney Brian Hauss said in a statement. “This law is an unconstitutional attempt by the government to silence one side of a public debate by coercing people not to express their beliefs, including through participation in a political boycott.”

The ACLU said it takes no position on the boycott of Israel or any other country.

Koontz, who said she shares her opposition to Israel’s treatment of the Palestinians with other members of her Mennonite congregation in Hutchinson, Kansas, sought a training position with the Kansas Department of Education’s Math and Science Partnerships program.

“You don’t need to share my beliefs or agree with my decisions to understand that this law violates my free speech rights. The state should not be telling people what causes they can or can’t support,” Koontz said in a statement. “I’m disappointed that I can’t be a math trainer for the state of Kansas because of my political views about human rights across the globe.”

While most of the largest Jewish groups have celebrated the passage of anti-BDS laws in Kansas and at least 20 other states, the ACLU suit drew support from the left-leaning New Israel Fund.

“No friend of democracy, nor any friend of Israel can, in good conscience, support this or any gag bill that silences dissent and erases the Green Line” marking the distinction between Israel and the West Bank, said Daniel Sokatch, CEO of the New Israel Fund, in a statement. “We don’t support the global BDS movement, but we’re grateful to the ACLU for its work challenging this damaging legislation at the federal and state levels.”