Governor Gavin Newsom went after Donald Trump Thursday following a judge’s decision to block the president’s mobilization of National Guard troops in Los Angeles. In a press conference, Newsom said he was “gratified” with Judge Charles Breyer’s decision that would return control over the California National Guard back to the Governor beginning Friday at noon.

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.