When not acting outraged over what he says, the political chattering class continues to shop the idea of an independent run for the White House by Donald Trump. Of course its conveniently couched in terms of such a bid ensuring a Hillary Clinton presidency.
Well, it may, but that may happen anyway if Mr. Trump is denied the GOP nod by the efforts of the increasing cadre of party people who say they will not vote for him if nominated. (Who will they vote for and isn't that threat just a problematic for the GOP as a third party Trump ?)
In any three way race, the Republican nomination would be devalued and the candidate would be in the shadow of Mr. Trump.
I don't think he ever mounts a third party bid for two reasons. One is his best path to 1600 is through winning the process he is in Second, independent bids are very expensive due to ballot access and the massive ad buys needed. That's likely more than the businessman wants to spend on an effort that would be a long shot.
If he starts losing GOP primaries, that wouldn't justify the expense of a third party bid. http://www.politico.com/story/2015/12/insiders-trump-independent-bid-would-ruin-gop-chances-216660