Chamberlain had a reason - UK army wasn't really ready for a fight. He tried to buy some time to rearm. Misguided or not, you could say there was a reason for that.
Chamberlain had seen many young people die needleasly in the nationalist ravages of the First World War and was trying everything to stop that from happening again, while rearming.
Not sure if he was misguided but he was certainly relatable. There are two solid reasons right there, that might notice been enough, but it certainly wasn’t a clear right vs wrong.
The Germans weren't ready for a fight either. As early in 1936 when Hitler marched a token force into the Rhineland, the French could have called his bluff there. In fact, even Hitler himself nearly called off his forces on sighting of french forces.
The Allies still had a larger and better equipped army at that point, the strategic mistake was having the French completely outflanked through Belgium, in which an earlier offensive with preexisting troops would have made it much harder to happen.
I agree with both you and AnotherGoodName - I should have been clearer.
It's not that I think Trump's actions here are equivalent. They are pretty clearly worse in motivation and objective.
I just think that we're going to head into a dark time for the world, and that future history books (if 2025-2035 goes roughly like 1935-1945, which I'm starting to think would be a horrific but "better than can reasonably be expected" outcome) that what happened at the White House today will occupy a similar place - a sort of last pretense of diplomacy before the storm, where one of the participants (Hitler in the original, Trump here) was never honestly interested in peace, just what they could gain in the short term via extortion.
