It appears that Trump "shot from the hip" in his response to the so-called gas attack, overriding the advice of the Pentagon and intelligence agencies. Possibly this is one of the reasons the US military has basically taken over the authority of the President as "Commander in Chief". Trump is much too volatile, pig headed and uninformed to be in charge of the world's largest and most powerful military. The Pentagon mostly likely were the ones who insisted that Russia be forewarned about Trump's temper tantrum.