I still wouldn't be surprised if Bill Clinton talked Trump into running for the purpose of causing chaos in the Republican primary. To weaken the nominee who they thought would be Jeb. It stroked Trump's ego being involved with the biggest show on earth - a presidential run under the banner of one of the two primary political parties, debates and all.
When Trump got some major traction telling people he was going to build a wall and deport all the illegals it caught all of them by surprise.
And here we are...