By Tom Hals, Jack Queen and Dietrich Knauth

(Reuters) -A trial in California challenging the legality of President Donald Trump’s use of U.S. troops in Los Angeles has highlighted vulnerabilities in American laws and traditions against deploying the military to carry out domestic police work.

San Francisco-based U.S. District Judge Charles Breyer is expected in the coming weeks to issue a ruling in the non-jury trial after hearing three days of testimony that ended on Wednesday. Gavin Newsom, the Democratic governor of the most-populous U.S. state, sued Trump after the Republican president deployed National Guard troops and active-duty Marines to Los Angeles in June amid protests against intensified federal immigration raids.

Newsom has called Trump’s deployment of troops an unlawful us

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