Let me go over, please, the serious arguments both for and against the American action in this regard.
Against this action--and I can think of only one argument (although it is fairly strong)--is the fact that Assad's benefactor, Russia, now seems poised to confront the US, militarily. In fact, Russia has now sent a destroyer to the eastern Mediterranean Sea, near the two American destroyers.
If the Russian destroyer should fire on one of the American destroyers, that firing would almost certainly be reciprocated.
In fact, Dmitry Medvedev--Russia's prime minister, and Vladimir Putin's right-hand man--has already declared that the US and Russia have gone beyond the stage of a proxy war, and are now engaged in an actual war with each other.
Of course, both Putin and Medvedev are well-known for their bluster; so this is not necessarily to be taken at face value.
For this action are a couple of matters, it seems to me:
For one, it sends a message to both China and its client state, North Korea, that there is a new sheriff in town; and the US will no longer tolerate rogue behavior. It will walk softly, and carry a big stick--rather than the other way around (as it was during the Obama years).
Moreover, to ignore the gassing of civilians would be to tacitly normalize this behavior. It would likely, therefore, become rather commonplace--ultimately, to the detriment of Americans.
Overall, I think the decision to strike Assad was a good one.
But it is better to analyze the matter seriously.
