Using the National Guard is clearly justified. Using the national military (in the case, the Marines) is...highly questionable.
That said, California should have been on top of this situation. It looks like Newsom is willing to sacrifice the safety of his citizens in an attempt to score political points.
The protests were all but entirely peaceful (as in, no more violent than your typical sports celebration) until the National Guard showed up. Newsom's far from my favorite person, but his handling of this situation was spot on, and he's bang on the money about deploying troops being a gross escalation.
That said, California should have been on top of this situation. It looks like Newsom is willing to sacrifice the safety of his citizens in an attempt to score political points.