President Donald Trump could be left off the primary ballot in California next year if he does not release five years of his tax returns, because of a new law that Gov. Gavin Newsom signed Tuesday. California is the first state to require presidential candidates to release their tax information, though lawmakers in at least 25 states have introduced similar legislation since Trump won the presidency. Although not required to do so, Trump was the first presidential candidate in more than 40 years not to release his taxes, and he has continued to refuse to reveal them as president. The law is likely to face legal challenges, but Newsom said his state is “well within its constitutional right”.