Dispirited by their failure to unite — and in despair over two terms of a Republican president whose initiatives frustrated if not horrified them and whose appeal befuddled them — the Democrats created Super Tuesday in 1988 so they could climb behind a consensus candidate and present a moderate face to the country. More than a quarter century later, the Republicans are experiencing the same despair over a president of the opposite party and, in the wake of Super Tuesday 2016, are suffering the same lack of unity — but they are on the verge of selecting a nominee who is anything but moderate.

As Donald J. Trump continues what seems a relentless march toward the GOP presidential nomination, there is great unease, even panic, in a party that a century ago was content to choose its nominee in the fabled smoke-filled room of Chicago’s Blackstone Hotel. It now must come to grips with the notion that it is being taken over by a force it did not anticipate expressing views it does not embrace in a rancorous rhetoric it does not countenance.

In creating a political movement with perhaps only one precedent in American history — the 1896 takeover of the Democratic Party by flotsam of the Populist Party to the soundtrack of the intoxicating rhetoric of prairie preacher and dreamer William Jennings Bryan — Mr. Trump has remade the party even as he has sundered it.

Since the Rev. Pat Robertson promised, or threatened, 28 years ago to bring a new cadre of religious conservatives into the staid old party of Robert Taft in the Senate and Gerald Ford in the House, Republicans have been remaking themselves. The Robertson right was succeeded by the insurrectionists of the Newt Gingrich era and then by the interventionists of the George W. Bush era.

Now the transformation is reaching a new phase. Trump Republicans have pushed aside the Madison Avenue Republicans, the Main Street Republicans and the Wall Street Republicans. They have trampled the Rotary Club Republicans and the country-club Republicans. They have mounted an assault on the Senate Republicans and the sensible-center Republicans.

With astonishing unity, the Trump Republicans have split the Republican Party and created a crisis of the Old Order, a phrase that historian Arthur M. Schlesinger Jr., a student of another disrupter, Andrew Jackson, applied to what happened to the Democrats, and to the country, from 1919 to 1933.

The divide among the Republicans is exemplified in two remarks delivered after the polls closed. ‘‘I am a unifier,’’ Mr. Trump proclaimed. Within the hour, Sen. Ted Cruz of Texas, consoled by victories in his home state, along with Alaska and Oklahoma, described Mr. Trump as ‘‘profane and vulgar.’’ The difference between the two messages, and the hostility between the two men, is heightened when you recognize that Mr. Trump and Mr. Cruz are trolling for votes in the same anti-establishment, anti-immigrant, anti-liberal stream.

So if the contenders who agree on the “anti-” platform and who once avoided conflict in the hope of picking off votes from the other’s tackle box, are that bitterly at odds, then imagine how wide is the chasm between them and, say, the congressional wing of the party (where House Speaker Paul Ryan, himself once regarded as the great theorist of the new GOP, and Senate Majority Leader Mitch McConnell, who luxuriates in his image as intransigence incarnate, are in anguish bordering on desperation); and the business wing of the party (which has never condoned the commercial practices of Mr. Trump, steeped in the casino culture and abetted by eminent domain); and the city-club drawing-room wing of the party (whose members, in their J. Press blazers and repp ties, speak in a tone far different from the bombast of Mr. Trump).

Mr. Trump throws rhetorical rocks while the party he dominates contemplates its legacy at Plymouth Rock. Mr. Trump boasts of his achievements while the party whose nomination he seeks recalls its antipathy to boasting. Mr. Trump sketches a bold, primary-color future for a party that once prospered with platforms printed in muted tones by men in gray woolen suits. Mr. Trump speaks in Allen Ginsberg howls in a party that, in the very year that the beat-generation poet released his book of the same name, spoke in Dwight Eisenhower whispers.

This is a cultural conflict for the ages, reflecting the cultural conflict of the age.

‘‘This is a new phenomenon,’’ says Michael Haselswerdt, a political scientist at Canisius College in Buffalo. ‘‘The political culture used to be insulated from the broader culture. Now the entertainment element is intruding on the political world. We have ‘reality TV’ in politics.’’

The reality of that intrusion is only now being recognized by the feudal overlords of the Republican Party, who are struggling to regain their suzerainty in a political world they hardly recognize.

They recognize the mathematics of the situation, however, with Mr. Trump on a glide path to a nomination they hoped to confer quietly on former Gov. Jeb Bush of Florida or another mainstream figure — a governor, perhaps, who knew how to deal with budgets and knew the difference between a line-item budget and drawing a line in the sand.

‘‘The rhetoric we’re hearing on the other side has never been lower,’’ former Secretary of State Hillary Rodham Clinton proclaimed as she claimed victory Tuesday night. That might be so, but that very rhetoric is coming her way, sooner rather than later, if the Republican establishment, or Mr. Cruz, or Sen. Marco Rubio of Florida, cannot figure out a way to halt Mr. Trump.

But the truth of the new age is that there really is no Establishment in the party of the Establishment, it has no meeting place to plot such an undertaking, it has no forum to prosecute such a counter-revolution, and it has little, or perhaps even no, time to organize it. And because Mr. Rubio insists on remaining in the race until Florida votes, and Gov. John Kasich insists on holding off any decision until Ohio votes, the opposition to Mr. Trump may be hopelessly divided — “a disaster for Republicans, for conservatives and for the nation,’’ in the weary words of Mr. Cruz — and the effort to overtake him hopelessly futile.