For me it has to be Malcom X, I’m not American, but I read his autobiography when I was young and it left a life long impression on me about justice and resiliency. He grew up in an extremely oppressive society, his dad was murdered and his mother was sent to the loony bin and he was clearly lost and traumatized. When he went to jail he was smart enough to be like what the hell, why am I here? Educating himself and channeling his energy into caring about others and justice transformed him into one of the most powerful and well respected leaders of his time.
He is often denigrated by Americans as violent and contrasted with King Jr. but by all accounts whenever he was in a position to project violence he chose de-escalation like during the Harlem riots and saved lives as there were people in the US in positions of military power who would have loved an excuse to do to them what they did to the indigenous across the entire country.
He was angry but principled and really set a template for me about how to be a leader and help me process my own anger and channel it into something more positive.
Churchill. Without him it’s not unlikely that the UK would’ve accepted Nazi Germany’s peace offer.
Neville Chamberlain originally did try appeasement with Hitler, yes, but he did declare war when peace talks broke down. He massively scaled up the armed forces before war broke as a signalled deterrent to Hitler.
Once it became entirely clear that the enemy could not be reasoned with, he stood down, having exhausted all the power he had to stop further escalation.
Churchill, in contrast, was an escalator. Perhaps what the country needed at the time, but so pig-headed that he wanted to keep the war going long after support from home had dried out.