In 2013  public support  was for a missle attack on ISIS not Syria and Assad (and Obam did that sending missles form Navy ships against ISIS targets) Both Repbulicans and Democrats were opposed to an attack on Assad. Obama's plan that he stopped at the last minute was for hundreds of missles directed at almost all of Assad's war making facilities and airfields and not just 59 missles directed at one airfield.  But Congress was opposed and Obama chose not to defy congress. Trump has chosen a narrow approach directed just at use of Sarin gas and he was very careful to say that. Assad and the Russians retain serious military assets in Syria. Al Quaeda and ISIS have just expressed support for the attack on Assad and Russia is making it more difficult to coordinate with Russia against ISIS but freezing communication. This makes the next step a diplomatic and not military.- Russia may not feat a limited strike like Trump's but it is better than nothing.