I suspect some are going to see this as a move by Paul Ryan to go against Trump, though it is not. Evan McMullin is the Chief Policy Director for the House Republican Conference and a former CIA staffer. He also worked at Goldman Sachs and, like Trump, went to Wharton. Today, he is an independent Presidential candidate.
McMullin has an uphill battle getting on the ballot in a number of states and, if he chooses, will have to relitigate in other states that have already closed access. There are arguments to be made that he should win those cases, but there is no word yet on whether he will even try.
Right now, the campaign says he will focus on Utah and states of high Mormon concentration because Trump does very badly with that constituency and McMullin went to Brigham Young. The campaign team around him says he is going to run this campaign to win, but right now it seems more likely to just provide Trump an excuse for his own loss.
Certainly if McMullin can get major funding and get his name out, he might have a shot at steering people in his direction. Already, Dan Senor is rumored to be backing him. The Kochs, I hear, are mulling it over as is Romney. If McMullin can get all of them on board, then suddenly there’s a race to be had.
Right now, though, he appears to be the candidate for Republicans who do not like Trump and nothing more. He’ll need to be more to win.