John McCain and Trump have history - I seem to remember Trump calling McCains not a war hero as he got shot down.
uk.businessinsider.com/donald-trump-john-mccain-war-hero-2015-7
From July 2015
Speaking at an event in Iowa, Trump argued that McCain — who has spoken out against Trump for his controversial comments about Mexican immigrants — was not a real war hero.
"He's not a war hero," Trump said. "He's a war hero because he was captured. I like people that weren't captured."
"Perhaps he's a war hero, but right now, he's said bad things about a lot of people,' Trump added.
I really hope no US soldier gets captured. I don't know how Trump would react.