He didn't really need to though, and he hasn't yet had time to work that bulletproof martyr/messiah message. He will, and will do it quite successfully. He's a good conman, and most voters are gullible idiots.

He was already ahead in the swing states. Incumbent presidents have nothing new to offer - they are by definition the same old, same old candidate. A replacement would be mired in dispute and confusion.

Trump is the shiny new: voters are dumb goldfish who don't remember 4 months, let alone 4 years.