Trump used just 59 Tomahawk missiles on one air base to send a very limited and specific message regarding chemical weapons.  The base is now operational again with planes flying missions from it. Obama was going to use the full military complement-- hundreds of Tomahawks launched from ships attacking many Syrian military facilities, to be followed by bombing once radar and communications were taken out (he with pressure from Congress wisely called it off at the last minute). So Trump was not the one expanding use of the military. I am not a Trump fan, but he was very restrained in his speech after the attack and said it represented only a message regarding chemical weapons and not an attack on Assad and Syria.