A federal judge in San Francisco is weighing whether the Trump administration violated federal law by sending National Guard troops to accompany federal agents on immigration raids in Southern California.

Lawyers for President Donald Trump and California Gov. Gavin Newsom are set to face off Monday to determine whether the president violated a 147-year-old law when he deployed the National Guard to quell anti-immigration enforcement protests in Los Angeles – against the wishes of the governor.

A fight between President Donald Trump and Democratic Gov. Gavin Newsom over the National Guard's presence in California will come to a head in a three-day trial.

Trump announced plans on Monday to send 800 National Guard troops to Washington D.C., as his California guard deployment is on trial.

Attorneys for Gov. Gavin Newsom headed back to court Monday over President Donald Trump ’s use of the California National Guard to subdue protests in Los Angeles, a tactic the White House is now repeating in the nation’s capital in what’s it’s calling a crime crackdown.

A federal judge in San Francisco will hear arguments on whether military troops deployed this summer by the Trump administration to Los Angeles violated a federal law that bars troops from conducting

A federal judge in San Francisco seemed unconvinced after a three-day trial that the continued deployment of federalized members of California’s National Guard — who were originally deployed to Los Angeles in response to protests against President Donald Trump’s immigration agenda — is lawful.

If President Trump deploys troops to other American cities, experts say it would be a clear departure from founding principles and invite a legal challenge.