Donald Trump, left, and Bernie Sanders. (Associated Press/Getty Images)

Both major parties have fractured. On the right, traditional Republicans cannot coexist with populists/nativists. On the left, mainstream liberals such as Hillary Clinton hold little allure for Western European-type socialists, who have found their leader in Sen. Bernie Sanders (I-Vt.). That Sanders would even contemplate a debate with Trump (which can only damage the Democrats’ inevitable nominee, Clinton) suggests he is moving out on his own, irrespective of the party’s wishes. (No self-respecting party leader would condone this, so perhaps Rep. Debbie Wasserman Schultz, chairwoman of the Democratic National Committee, will head this off.)

In essence, in addition to Libertarians, we have traditionally conservative; right-wing populist; mainstream liberal; and socialist subsets of the electorate. The differences between traditional conservatives and Trumpkin populists are so vast that the former have more in common with Clinton on foreign policy, trade and some semblance of fiscal sobriety than they do with Trump. Trump, meanwhile, has more in common with Sanders on trade, isolationism and anti-Wall Street fervor than either does with his own party.

Rather than a third candidate, we should have Libertarian Gary Johnson, a fourth candidate (a center-right conservative) and a fifth (socialist Sanders). It would be an accurate gauge of which ideological grouping has a real following. It would make certain that the four mini-parties each had a standard bearer and it would be a test as to whether any of them have appeal beyond his or her niche. Can, for example, a center-right conservative pluck off some moderate Democrats? Can Sanders really swallow the entire Democratic Party?

It certainly would make for an exciting race. But wouldn’t this all wind up in the House of Representatives? It could, certainly. But once the Democratic side is fractured, Republicans might decide it pays to rally around a more traditional center-right candidate so they aren’t helping elect Clinton.

We are in unstable times, in which frustrations with the major parties explode right and left. The collapse of the two parties  takes us into new terrain. Rather than try to contain and suppress the rebel movement in each party, the only way to lance the boils of angry populism on the right and left may be to let them independently test their electability. We might find out there’s nothing left of the old Democratic Party or we might find out Sanders represents a sliver of the electorate that better learn to live with other Democrats.

Remember that not all candidates have to run everywhere. Sanders, for example, could run primarily  in New England, the Northwest and upper Midwest (so forget the Texas ballot requirements and the South altogether). Mitt Romney (or whoever) could run hardest in the Plains, Indiana, Ohio, Utah, North Carolina and Florida. From the positions of both the #NeverTrump and #NeverHillary forces, there is a fighting chance to stop their nemeses and get to the House, where just about anything can happen and the popular vote becomes a factor in state delegations’ consideration.

If this sounds bizarre, remember what other bizarre occurrences have transpired this year. Alternatively, take a look at the election of 1860, in which four reasonably competitive candidates faced off, each with a regional base. (The result turned out, ultimately, to be the savior of the republic.)

It is not likely that this multi-candidate race will pan out. However, if Sanders wins California, Romney gets into the race and Trump continues his search-and-destroy mission against Republicans, things could get really interesting.