There were things I did like about his politics. Most importantly, he pushed the Bush - Cheney administration away from torture; without him it's plausible that our official policy on torture would be no different from that of dozens of dictatorships around the world.
Beyond politics, I'm not sure how you would dislike his person. A man who nobly stayed a prisoner of war for years rather than leave behind his fellow prisoners - a price that cost him, among other things, his ability to raise his arms above his head - is a man you can't help but respect.
He was an icon of the Republican Party and yet Trump attacked him.
Even though he was not running against McCain in the primaries, Donald Trump went out of his way to say that McCain was not a war hero. "I like people who weren't captured," said the man who claimed that his own personal Vietnam was avoiding sexually transmitted diseases at Club 54 in the 80s and who avoided being drafted into Vietnam because of "bone spurs." Trump made more than one enemy with that comment.
Trump has also - repeatedly - shown disrespect towards all the former Republican presidents named George Bush.
Here's Trump's remarkable achievement. To side with him, you have to side against both living, former Republican presidents and one of the party's most iconic figures and former candidate for president in John McCain. He has repeatedly shown contempt for those men. They have repeatedly made clear their disdain for him.
Trump has forced his supporters to choose between him and *
- American prisoners of war
- a gold star family (a family who has lost a child in combat)
- every living former Republican president
- the FBI
- his own Attorney General Jeff Sessions
- the American Intelligence community (which includes the CIA)
- Economists who argue for multi-lateral trade agreements like the WTO, TPP, and NAFTA (which includes the overwhelming majority of economists)
- the Editorial boards on 100 of the nation's top 102 newspapers (of the two newspapers that endorsed him for president, one was owned by Jared Kushner, his son-in-law)
- iconic conservative voices like George Will, David Frum, and David Brooks
And Trump has succeeded in this. Republicans have sided with him over all these opponents to his policy and person.
In spite of making enemies of every living Republican candidate for president and every former Republican president, Trump's approval rating among Republicans stays close to 90%.
Based on this, I think it is safe to say that no president has - in my lifetime - changed a party more. Republicans not only love him but are willing to side against so much of what past Republicans have sided with to do that. Most recently they have happily joined with him in his contempt for McCain. (40% of Republicans disapprove of McCain.) To redefine a party that much is an incredible accomplishment.
* And of course as time goes on, the list of people Trump supporters have to side against grows. His former allies who have turned against him immediately end up on his enemies list. His former lawyer and confident Michael Cohen and former adviser Omarosa Manigault are just the most recent of the people who his supporters had to once revere and now disrespect.