Pretty much tipping his hand here that he’s gonna go third-party.
I hope he doesn’t but the Republican Party has given Trump every justification to go 3rd party. #NeverTrump is going to give them #NeverWin. Even down-ballot.
If that’s his goal, he has to start before the convention. He would need to gather signatures in each state, and by the time of the Republican convention, will have already missed the filing deadlines for 12 states, including Texas, Florida, Illinois and Indiana. With those not in play, he would have no choice of doing anything but preventing the Republican nominee from winning. (Texas has the earliest deadline, May 9, so he’d have to start gathering signatures now.)
That would make sense as going 3rd party would help get his friend Hillary elected, which has been Trump’s goal from the start.
Wait until he finds out about what happens when you only win a plurality of electors under the 12th Amendment. Of course that probably won't happen until after the election.
If he goes third party it will probably have to be as a Libertarian. I think if he goes a “Trump Party” he’ll only be able to have a vote in 16 states due to missed deadlines, etc.
I doubt that but he certainly is going to make a dogs breakfast out of the existing Republican monopoly.