Trump is unfit and unworthy to be the Commander-in-Chief. End of story. He should not make a spectacle of the presidential nomination and election process. It is already bad enough without the media giving him a platform for knee jerk gags and laughs and shifting the debate in senseless directions and diverting the already meager and meandering attention of the public.
Our nation continues to face significant economic, diplomatic, and social challenges domestically and internationally. The US will need a respected Commander-in-Chief, someone who can be respected at the bargaining table with friend and foe alike, and have an even temper to handle the pressures of international diplomacy (see: Ukraine; see: Iran.) I can only imagine the national harm Trump could cause based on his immature outbursts.
But Trump is about Trump. He is happy to make a circus of the Republican nomination process even though he know he won't win.
Btw, I have no problem with Trump calling out someone. The problem is how he framed it about honoring winners not losers. It wasn't a specific criticism of McCain's service record (does he deserve to be a hero?) or McCain's politics (which I don't like personally) but the fact he clearly was slamming POWs -- as if every war hero is going to be, "American Sniper." What an idiot. Getting shot down and captured has as much to do with luck (where were you? What sortie? How many shot down? Was your capture important to cover for others or even to save others?) McCain put his life on the line. Unless someone can show he failed to do his duty or failed to attempt to execute his orders what happened to him (success or failure) the bottom line is he deserves our respect for his sacrifice of service.