An escalating clash pits a Republican president looking to fulfill his mass deportation goals against a Democratic governor with White House aspirations hoping to mobilize opposition.

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.

Gov. Gavin Newsom and other leading California Democrats criticized President Trump’s deployment of National Guard soldiers in Los Angeles, calling it an unnecessary provocation.