Now that Trump has left the GOP which leaves the door even further open for him to run as a third party candidate, the GOP faces inevitable defeat if it nominates Romney. The details of a possible electoral college scenario are set out at the link.
With Gingrich as the nominee I believe that Trump might not run, as I would be confident Trump would not consider Newt to be "a stiff." But given Newt's current front runner status nationwide, the fact that Trump still left the GOP gives one pause.
The only potential candidate who would almost certainly stop Trump from mounting a run, and really, can any honest observer see a path to electoral college victory for the Republicans under those circumstances, is Palin. Trump clearly respects Palin as a person and her political point of view. If she ran, he would most likely not only not run, but throw his substantial personal voting support and finances behind her.
In a wide ranging interview with Greta Van Susteren Donald Trump made it very clear that under certain circumstances he would run for president under a third party banner. "If I don't see the right person running I would certainly consider it."
Trump advised he saw the GOP "self destructing", the Republicans having a "death wish and making terrible mistakes." These include specifically Cong. Paul Ryan "suicidal" health care reform plan "which should never had been released-he should have made Obama bring out a plan first, this is a disaster for the Republicans for 2012."
Trump advised that "if I had my choice I'd love the Republicans to run someone fabulous-I don't see that happening yet." He advised that "since I decided not to run at this time no one is talking about China" which is a major issue for him, and for America as he sees it.
Pressed on whether he would get back in the race he pointed out that, unlike Perot he never declared he was a candidate, and there is "plenty of time to decide-I would make the decision based on who is running and if they (the GOP) "put up a stiff, if they do I would certainly consider running in a three person race where I would probably do better than in a two person race."
He was highly complementary about Sarah Palin who he called a "patriot who loves America" but stopped short of endorsing her at this point. He appreciated her sharing his concern about the economic threat that China poses to America especially.
Presuming by "a stiff" Trump means Romney as the Republican nominee, and if the economy is still mired in recession, which is the other key factor for him, then a self-financed, high profile,"man of the people" campaign would mean certain defeat for the GOP.
Trump has made the options for the Republicans totally and starkly clear-run with either Romney, and turn possible defeat into certain defeat, or run with Palin and presumably remove the third party threat. Palin might win or might lose, but Romney will certainly lose under the Trump scenario.
Michael Potemra at NRO almost gets it right but one of the commentators hits the nail on the head
"You clowns miss the whole point. Sarah Palin is insuring that Trump doesn't run as an independent should she run for president."