The Republican Party is nearly powerless to pull back from anointing Trump its presidential nominee, even as he continues to repudiate America's commitments to racial and religious tolerance and multilateral national security and economic policy. Although there are efforts to block Trump at the GOP convention and through a legal challenge, here is the reality: Party rules dictate that the nomination is decided by a majority of delegates who are selected through the primaries and caucuses. Trump secured a majority weeks ago.

The Democratic Party had its brush with a similar political disaster in 1972, when Alabama Gov. George Wallace fought to a three-way tie in the race for the party's nomination. Famous for his racist crusade for "segregation now, segregation tomorrow, segregation forever," Wallace stirred intense emotions and was riding high when his threat to become the nominee was cut short by a would-be assassin's bullet.

The potential for candidates like Trump and Wallace to hijack major-party nominations raises a difficult question: Should political parties operate as pure democratic vessels that mirror the wishes of those participating in primaries and caucuses? That's Trump's position, of course — and Bernie Sanders'.

Thinking-cap time. Three issues:

1) The idea that political parties should be purely democratic is a peculiarly American obsession. In Britain — and other European countries — national and local party leaders choose nominees. Democracy remains vibrant in these countries but is defined as the battle among the political parties — not within them, as in America.

The general-election showdown pitting Hillary Clinton against Trump (or, if lightning strikes, one of his conservative Republican rivals) poses a clear, stark choice for voters. That contest of dueling parties, platforms and visions constitutes the practical expression of representative democracy that we see in Europe and elsewhere.

2) It is absurd to equate democracy with deference to primary and caucus voters. This year, only about one-quarter of all eligible voters participated in selecting the nominees. Twice that many (or more) are likely to vote in the fall. Today's champions of making nominations "democratic" are perversely advocating for a small minority to choose the candidates from which the majority will be forced to select. What kind of "democracy" is that?

That's not all.

Primary and caucus voters are not even representative of citizens who will vote in the fall's general election. Let's take a peek at the exit polls of voters and compare the smaller and more narrow group of citizens who showed up in each party's primaries and caucuses this year with the larger and broader group of voters who participated in the 2012 general election. Exit polls in 2016 among Democratic primary and caucus voters show that they were about twice as likely to identify themselves as liberal as voters in the 2012 general election, and were substantially more diverse. Republican primary and caucus voters this year were about twice as likely to be conservative and white, born-again or evangelical as voters in the 2012 general election. Only 8 percent of Republicans in this spring's primaries and caucuses were people of color; in this fall's electorate, that group may be about four times as large.

Demands to "let the people" decide the nomination are presenting a mirage — one that empowers relatively small cliques over the majority of citizens.

That's a lot to digest. One more big issue.

3) Political parties are bulwarks against extremist threats to our shared values, including respect for the Constitution and the rule of law. Donald Trump — much like George Wallace — threatens our country's foundation. We don't want our presidential nominations to become spectacles in which the shrillest voices prevail.

What can be done? A daunting question that lacks a simple answer.

First, an appreciation: Primaries and caucuses gave voice to tens of millions of people this year — many of whom seethed with frustration and anger. We want that intense disquiet released publicly rather than festering in the shadows and becoming a reservoir for social disorder. For all of Trump's flaws, he has helpfully spotlighted the many Americans who feel ignored and abused by our country's political establishment. This is a wake-up call for both political parties and points to a value of primaries and caucuses.

This brings us to the Democratic Party's "superdelegates." They were invented as a mechanism to retain the voice of party activists while also weeding out extremists in favor of candidates with genuinely broad appeal. About 85 percent of the delegates to the Democratic convention were chosen in the primary and caucus process, while 15 percent are current and former elected officials and senior party leaders.

The structure originated, in part, as a response to Wallace's rise and the realization that a purely democratic nomination process in a crowded field (sound familiar?) could create an opening for an extremist candidate.

Making the case for superdelegates may initially offend your predilection to support all things democratic. Our counsel: Resist that impulse. Equating democracy with the primaries and caucuses on false premises opened the door to Trump and Wallace.

Party leaders are not saints. But we know what makes them tick — the hunger to win elections and keep themselves in power. Their incentive to choose broadly appealing candidates who can win the general election is a predictable weather vane.

If the Republican Party had superdelegates, Donald Trump would not be the party's nominee. Similarly, had the Democrats had super delegates in 1972, Wallace would never have been in the mix.

Lawrence R. Jacobs is director of the Center for the Study of Politics and Governance at the University of Minnesota's Humphrey School of Public Affairs. Vin Weber is a partner at Mercury, a public-strategies firm in Washington, D.C. From 1980-92, he represented Minnesota's Second Congressional District as a Republican in the U.S. House.