You're focusing on the absolute worst case scenarios, which are the least likely, by definition.

One possibility is that Trump gets his feelings hurt by a head of state, or fails a trade deal, or something equally existential, and tries to order a first strike in a fit of pique. Odds of success: Asymptotically approaching zero. Too many people will question it and push back, delaying implementation until the 25th Amendment strait jacket can be fitted.

The other branch of the scenario tree is the one you're hitting on, acting fast in the event of an attack. I'm as sure as you that Trump would blow it if it came down to the scenario of shaky information and little time, but consider that the only even semi-credible source for such an attack is North Korea, probably on my head. So when it comes to recognizing an attack and responding properly, there's really only one place we need to keep an eye on.

There are little signs that the US military has been building up a west-facing defense for years now, and one thing you can count on, there will be no false alarms from all the radar stations in South Korea keeping the North under intense surveillance, and we won't miss the launch either.

You'd know this one: How's it going with the airborne laser? The one that would have a perfect base in South Korea to hit a missile in the North during boost phase. Whenever a weapon system development program drops from the news, I figure it's operational.

Anyway, I'm not arguing against the absolutely possibility of Trump burning down the country. Or the world. I'm just trying to make a graduated risk assessment.

Odds are much higher that Trump will burn down the economy, civil rights, the environment, and democracy. Stay tuned.