LOS ANGELES >> President Donald Trump will not be eligible for California’s primary ballot unless he releases his tax returns, under a new law signed by Gov. Gavin Newsom today.

The law requires that all presidential candidates release their tax returns in order to be placed on the ballot for the state’s primary next year, in a move that will almost certainly lead to legal challenges. Newsom’s decision to sign the legislation seemed designed to escalate the running feud between the White House and California.

The state is currently involved in more than 40 lawsuits with the administration on issues ranging from the environment regulation to immigration.

Similar legislation was previously passed in 2017, but Gov. Jerry Brown vetoed it, questioning whether it was constitutional. Brown, who left office in January, also said it would create a bad precedent for requiring other information — including medical records or certified birth certificates — from candidates.

Newsom sent mixed messages on whether he would sign the law, but finally did so on the last day before the bill would become law without his signature. The legislation does not explicitly cite Trump, but lawmakers made no secret that he was the target when they passed the bill along party lines.

The law, which goes into effect immediately, requires any presidential or gubernatorial candidate to submit copies of their tax returns from the last five years with the California secretary of state, at least three months before the state’s primary. That means Trump would have to provide his tax returns by the end of this year.

“These are extraordinary times and states have a legal and moral duty to do everything in their power to ensure leaders seeking the highest offices meet minimal standards, and to restore public confidence,” Newsom said in a statement as he signed the legislation. “The disclosure required by this bill will shed light on conflicts of interest, self-dealing, or influence from domestic and foreign business interest.”

The governor cited several legal scholars who signaled support for such a requirement, but it will probably be left to the courts to decide.

Tim Murtaugh, a spokesman for the Trump campaign, declined to comment on potential lawsuits, but called the legislation unconstitutional.

“The Constitution is clear on the qualifications for someone to serve as president and states cannot add additional requirements on their own,” Murtaugh said. “The bill also violates the First Amendment right of association since California can’t tell political parties which candidates their members can or cannot vote for in a primary election.”

The Trump campaign, which has been tracking ballot access issues carefully for months and coordinating with the White House Counsel’s Office, is likely to respond with a lawsuit, according to an official with the campaign. That suit could potentially include a number of plaintiffs, including the Republican National Committee, the California GOP and the Trump campaign, but the official warned that nothing about a suit had been finalized.