By the time it ended Process_end , California had gone from a thinly populated ex-Mexican territory , to having one of its first two U.S .

He therefore committed Commitment his main strength to besieging Besieging the city , leaving Departing the front line only thinly held Defending .

This , and terrain that favored Causation the defenders , threw Causation the German advance behind schedule and allowed Preventing_or_letting the Allies to reinforce Cause_change_of_strength the thinly placed Placing troops .