Judicial Watch said Monday it was representing four California voters who sued to stop the state from requiring President Donald Trump from disclosing his tax returns in order to appear on the 2020 primary ballot.
The registered voters sued California Democratic Secretary of State Alex Padilla in federal district court in Sacramento. They include two Republicans, an independent, and a Democrat, the conservative watchdog group said.
Last week, California Democratic Gov. Gavin Newsom signed legislation requiring presidential and gubernatorial candidates to disclose their federal returns for the five most-recent taxable years to appear on the state's primary ballot.
Under the law, the candidates must provide the data to the California secretary of state at least 98 days before the requisite primary election.
According to Judicial Watch, the taxpayers contend California lacks the authority to impose such requirements on candidates.
The law goes beyond what the U.S. Constitution requires for presidential candidates, the action contends, as well as violates the plaintiffs' rights under the First and 14th amendments.
"California politicians, in their zeal to attack President Trump, passed a law that also unconstitutionally victimizes California voters," Judicial Watch President Tom Fitton said in a release announcing the lawsuit. "It is an obvious legal issue that a state can't amend the U.S. Constitution by adding qualifications in order to run for president.
"The courts can't stop this abusive law fast enough."
Newsom's predecessor, former Democratic Gov. Jerry Brown, vetoed a previous version of the measure in 2017, arguing it might be unconstitutional, The Hill reports.
President Trump's personal lawyer, Jay Sekulow, has said the California law would be answered in court.