Given the enormous difficulty in determining, due to inability to get any independent party in there to verify, whether this was Assad who launched the gas attack or whether it came from stocks held by ISIS this is a very high risk action.
Not condoning its use in any way - its illegal under UN rules (& common humanity) whoever does it, but this action is probably typical of the way Trump (& some of his newer advisers) will act & does not bode well for other potential flash point areas (N Korea anyone?)