The state of California had sought to stop the president from sending National Guard troops without the governor’s approval.

Democratic politicians have spent the last few months talking about standing up to President Donald Trump in his second term. California Gov. Gavin Newsom is among the first faced with figuring out what standing up actually looks like.

What the judge rules, and the likely appeals that follow, may alter decades of understanding about the roles of governors and the White House in quelling domestic unrest.