Let's compare Obama to Trump.

The US warned that the use of chemicals was a "line in the sand" that would provoke a US response.

Obama's response?  I think it's fair to say that Obama's response was similar to the lily-livered responses that Neville Chamberlain gave towards fascist aggression in the 1930's.  "Peace in our time!" - and we all know how that songbook played out.

Trump's response? Well let's just say that after years of Obama's failed policies in Syria, we're finally seeing some definitive action against the atrocities, and it's about time!  Perhaps Assad will finally get the message that the killing of innocents in Syria will no longer be tolerated.