PHOENIX (AP) — The American Civil Liberties Union filed a federal lawsuit Thursday for an attorney challenging an Arizona law prohibiting state contractors from supporting boycotts against Israel, saying it violates his right to free expression.

The lawsuit was brought on behalf of Sedona attorney Mikkel Jordahl, who provides legal advice to Coconino County inmates. It is asking the court to declare the law, which mandates contractors sign a statement promising not to boycott Israel, unconstitutional.

"The government has no business telling people what causes they can or can't support," Kathy Brody, ACLU of Arizona legal director, said in a statement. "The bottom line is that political boycotts are a legitimate form of non-violent protest, and they are protected by the First Amendment."

Arizona Attorney General Mark Brnovich and multiple Coconino County officials have been named as defendants in the lawsuit.

Jordahl, who is self-employed, has been giving legal support to people detained in Coconino County jail for the past 12 years. He also has long demonstrated his personal pro-Palestine beliefs by not buying products and services from businesses that support Israel.

After the Arizona law took effect in March 2016, Jordahl received documents to renew his contract with the county seven months later. The paperwork included a form certifying he was not engaged in any Israel boycotts. Jordahl said he signed it under protest. He received the same form last month.

Jordahl said he wants to offer legal aid to organizations engaged in boycotts against Israel but this law would stop him. Refusing to sign the statement would mean a loss of income.

Ryan Anderson, a spokesman for the Arizona attorney general's office, said officials hadn't seen the lawsuit. But they are aware of the language in the law and that there have been legal challenges to similar laws in other states.

The ACLU in October filed a lawsuit to overturn a similar law in Kansas. A federal judge is considering whether to block enforcement of the 5-month-old law while the lawsuit proceeds. The suit was brought on behalf of a Wichita educator who was told she couldn't be paid by the state to train teachers because she refused to sign a statement that she wasn't boycotting Israel. Kansas officials said the law allows the teacher to seek a waiver.

The Arizona lawsuit comes a day after President Donald Trump declared Jerusalem as Israel's capital. Trump's decision breaks with decades of U.S. policy and set off a wave of clashes between Palestinians and Israeli forces. Both Israel and Palestine have laid claim to Jerusalem.