The irony is that (for anyone with a brain) Trump is a coward. He's the archetypal bully - and underneath it all is living a terrified coward.
He's lived off daddie's money his whole life and is deeply insecure.
He's the worst kind (an irredeemable, selfish, narcissist) coward, and if it came to actually protecting the American people if the US was threatened, I have absolutely no doubt that he would do whatever it takes to save himself and throw everyone under the bus/bomb to do so.