We haven’t seen any evidence to date.
We’re told that there is evidence an agent was used. But we’re not given evidence that Assad or his forces did it.
I suspect that Trump is holding off for just that reason.
Who wants the USA to stay in the region? There a lot of them. Which ones had the means, motive, and opportunity? There are a lot of them.
My guess is that Pres Trump is trying to sort that out.
In times of war, the public is not entitled to secret evidence.
McCain and Graham said it is true, so it must be!