Here's a little thought exercise:
What would happen if Donald Trump did last all the way up to the Republican convention in 2016, with enough delegates to even win the nomination to run as President... and the Republican party leadership is the one that bolts to run a third-party candidate instead of him?
It's an odd thought, I grant you, but it's one that might play out.
This came to me while reading up on reports of how Virginia and North Carolina's - and perhaps more states - local officials were re-writing their rules - rigging the game again, eh boys? - to require for each candidate to pledge NOT to run as a third-party or independent candidate in the general election. It's a rule clearly aimed at the one candidate who defiantly remains open-minded about the idea (Trump) and who was hit with that pledge with the very first question at this past August debate.
Deal is, such a pledge is meaningless: if the candidate who bolts is willing to risk it, to risk his standing in the GOP afterward, he'll do it. (It's happened before by the way, hi Pat Buchanan!) Trump owes the Republican Party nothing, regardless of the success he's having now as the lead candidate going into 2016. Part of the reason the GOP leadership is pushing this idea is based on pure ego: they want to rein in their wild cards, try to (re)establish themselves as The Boss Of You All. They want to set it up so that if Trump does bolt on an independent run, he'll look like a rule-breaker / oath-breaker.
Trump could still do it anyway. He could argue - rationally - that the pledge is a joke, skewed against only him in the first place, and that the party leaders themselves are rule-breakers for trying to implement such a code at this late hour. His voting base would easily agree with him on that (they mistrust the Establishment already).
But here's the thing: Trump right now doesn't even have to think about bolting. He's in the lead, by an absurdly comfortable number in most polls. He's got the largest factions among the GOP base - the anti-immigrant nativist crowd - backing him, and he can well get enough delegates to even clinch the nomination outright in Cleveland this 2016. Threatening him with pledges to stay in the party does nothing but alienate his followers into convincing themselves ever more that the Republican leadership does not care about "their" rights/issues.
The only thing the Republican Establishment - the ones backing "rational" players like Bush and Walker, who are both struggling to even make themselves coherent to their audiences - have going for them is the very thing any party fears this day and age: a brokered (broken) convention where no one goes in with a clear count of delegates. That means keeping as many candidates afloat in this election cycle than they've ever done in ages (if ever: usually the delegate counts narrow down to two clear choices with a dark horse compromise waiting in the wings).
This is actually easy to do this election cycle. With so many Active-Negative types (ambitious muthahumpers) running, few will want to volunteer to drop out. And if they play the long game out, each candidate would see the benefits of staying in the race all the way to the end: any sizable delegate total weakens everybody else, yet gives each of them enough playing chits to demand a seat at the table when the back-room deals are hammered out.
If the Republican leadership can go into a Cleveland convention center with six or seven serious players - Trump, Bush, Walker, Rubio, Cruz, maybe Huckabee, maybe Kasich, maybe one other - they could finagle a deal where they win out (with their boy Jeb!) and make Trump accept some peace offering. But that will only work if Trump is nowhere near the lead...
However, if Trump is in the lead - although without a clear win - there's no guarantee he'll give up his spot. He'll claim a win is a win, and will use any trick left in the books the GOP can't write out of the Roberts Rules of Order to muddle the convention until he gets the coronation he desires. And with enough delegates and with that threat of a third-party run - which could easily break the GOP in two as Trump's faction is clearly large enough to matter - Trump could get that nomination.
But will the rest of the Republican Party accept it?
In this scenario, Trump is coming in as the lead nominee but not the clear one. He won't have the over-50 percent count of delegates, after all. If we're looking at the current polling - Trump tends to sit at 24 to 33 percent of potential GOP voters - we should consider Trump getting around a quarter to a third of the party's vote. That means there's at least two-thirds of a party that did not want him... which will definitely include a party leadership terrified that Trump's reckless campaign style can hurt their entire ticket. Control of the Senate is clearly at stake this 2016 cycle, and the Congressional and state elections hang in the balance as well.
In this scenario, Trump may win the nomination for the Republicans but could clearly represent a hate-driven agenda that could depress voter turnout among the Republicans who didn't want him. Trump will affect the general election count as his open hostility towards immigration - and open hostility to competent governing - will alienate the middle-third centrist/moderate voters. If he's at the top of the ballot running on that platform it's good odds the rest of the GOP ballot will get shunned by the centrist/moderate voters too.
There is no guarantee with this fractured ballot of 16 candidates (with at least SIX viable choices who could go the distance) that the rest of the party will fall into line behind the eventual nominee (even if it isn't Trump). A dispirited party would hurt the other races down-ballot. In the face of this disaster, the Republican Establishment could well encourage one of their own to jump in as a last-minute Independent third-party run.
This depends on if states will allow new names on the ballot post-convention period. Another likely scenario would be to have a minor third-party group - oh where is the Reform Party when you need it? - able to get on all states' ballots. It is possible to pull it off.
Would the Republicans risk splitting their spot on the top part of the ticket? If it meant keeping enough Republican voters invested in turning out, they would.
But who would?
The person who does this runs the risk of being labeled a party pariah for the rest of his political career (the Far Right wingnuts in particular will never forgive him). It has to be someone who can command enough voter turnout to stop Trump (over 10 percent of the voters) yet convince the Republican base to vote well for the whole ballot.
There are few who could pull it off. Jeb! Bush would have the means - more money than God, especially if the Koch Brothers still back him - but not necessarily the motivation, nor the fortitude to step outside his own comfort zone. If there's no guarantee Jeb! gets the White House out of this move - this would likely keep Trump from winning but the Democratic candidate will be the clear winner in a three-way contest - he won't do it. Walker perhaps, again with proper deep-pocket funding, but if he wasn't able to out-pander Trump in the first place he might not have enough of a fanbase left by then to pull this stunt off.
Cruz won't. Partly because he's not on good terms with the Establishment faction in the first place. And if it ever gets to where he realizes he can't out-pander Trump, he's likely to offer himself up - despite his ego - as Trump's VP choice.
Rand Paul is a likely third-party guy since he could in theory pull off a switch to the Libertarian party if it becomes clear he won't win the GOP nomination. But would he pull enough Republican voters away from Trump while ensuring those voters still back GOP candidates for the Senate and the House?
The only remaining possibility who could and would attempt a third-party run would be the likes of Huckabee, especially if Trump stays on his own message that Planned Parenthood is "okay for women." If he's convinced Trump is not pure on the anti-abortion stance, Huckabee would make that run claiming a spiritual mandate to do so.
Nobody else would have a support base able to pull off that move. The Republican establishment would be hard pressed to find any volunteer to third-party against Trump even if it was for the "good of the party" (applies to the leadership only. The voting base is making itself very clear their feelings on the matter).
As a thought exercise, this didn't go very far. If Trump is at the lead of the delegate count going into Cleveland, the Republican Party is going to have to live with certain facts: Trump won those delegates "fair and square" on a virulently racist anti-immigrant campaign, which reflects on a Republican voting base that supports such hatred. In this scenario he's the likely GOP nominee out of the convention.
It's also likely that Trump - having campaigned so hard on that issue - will be unable to "turn back to the middle" of the regular election campaign to woo over any centrist/moderates (this is why the 2012 postmortem by their own experts argued FOR immigration reform as something the Republicans needed to pass themselves). If the Republicans could have gotten Jeb! or Rubio past the finish line - one of the "soft on immigration" candidates who really are not that soft - they'd be in a better position to convince the media (and the public) that their nominee is "moderate" enough to win the votes.
It's also likely the Republicans are stuck: without a viable candidate able to beat Trump in the first place, they're unlikely to have a shot at running a smart third-party alternative to keep Trump from forcing the Republican Party to collapse under the weight of his own Id.
This isn't a fun thing to watch, though. We are as a nation running a huge risk of having a neophyte impulsive egotist in Trump becoming responsible for policy decisions that affect the entire world. If Trump does win the Republican nomination, it may not benefit the disgruntled party leadership to run a third-party candidate to weaken Trump's campaign... but it certainly will benefit the nation from keeping Trump out of the Oval Office.