American presidential politics are now in uncharted and turbulent waters. The key to Donald Trump’s success in the primaries and in thrashing the mainstream Republican party, which sank without a ripple apart from the hundreds of millions of dollars it had squandered to pick up only about 20% of the vote, was that he was neither complicit in the blunders of the George W. Bush regime nor compliant in the blunders of the Clinton and Obama regimes.

Mr. Trump represented revolutionary change in style and moderate change in policy, apart from a radically new attitude to illegal immigration, trade deals that imported unemployment, and the back-scratching, log-rolling ambiance of the great Washington sleaze factory. He would neither charge blindly into foreign wars as George W. Bush did in Iraq, nor roll over like a poodle for Iran as Mr. Obama has.

Hillary Clinton’s campaign is the ultimate last stand of continuity. She privately dissents from Mr. Obama’s appeasement of Iran, and her husband has openly debunked Obamacare. But Mrs. Clinton can neither alienate the Obamas nor run on business as usual, and her entire campaign has been based on a savage denigration of Mr. Trump as a deranged, boorish, megalomaniacal racist, and sexist monster.

This was always a fragile strategy, as it depended on Mr. Trump to behave as a rampaging bull spluttering out self-destructive nonsense, as he did through the birther and “Mexican judge” and Khan affairs (although the Democrats’ manipulation of Mr. Khan was pretty tasteless). He did the necessary to rope in the Archie Bunker vote. After securing the Republican nomination, he became a good deal less accident-prone and gained appreciably in the comparative polls after the pop Mrs. Clinton got from the unity fest at the Democratic convention.

It was generally assumed that past comments of Mr. Trump’s would be extracted and deafeningly amplified by the uniformly hostile press led by CNN (Clinton News Network) and the (Never Yes to Trump) New York Times, news outlets incapable of a fleeting moment of impartiality. As the candidates appeared to be about even in the polls but with the Trump rise stalled, it was a piquant irony that the grenade that was lobbed was an open-microphone recording by a cousin of George W. and Jeb Bush, disclosed by the Washington Post, wreathed still with the laurels of the Watergate character assassination of four decades ago.

(Bob Woodward appeared on Sunday night just before the debate to give Bill O’Reilly his po-faced assurance that there was no relationship at all between the journalists and the editorialists at the Washington Post. I believe the needless Watergate hecatomb is the principal reason for the decline in quality of candidates for national office since Reagan.)

The Billy Bush clip released on Friday was extremely crude and boastful, almost disgusting for the seeker of the presidency of the United States, even though it was eleven years old. It was not as distasteful as the antics of a number of presidents, including JFK’s telling an intern to fellate one of his key aides in the White House swimming pool, and asking her to lie down in his official car so she would be invisible to the British prime minister (Harold MacMillan); Bill Clinton’s receiving oral sex in the Oval Office while ostensibly conducting government business on the telephone; or much of the routine conversation of Lyndon Johnson.

Thomas Jefferson, who famously held the equality of all men to be “self-evident,” was so pleasured by his slave Sally Hemings that she bore him seven children. Van Buren’s vice president, Colonel Richard Mentor Johnson, lived with an octoroon slave woman as congressman and senator a five-minute walk from the slave market in Washington for 25 years. Presidents Grover Cleveland and Warren Harding sired children out of wedlock; the extramarital, pre-presidential affairs of Franklin D. Roosevelt and Dwight D. Eisenhower almost broke up their marriages, which would have disqualified them for the presidency (and FDR revived the relationship in his third term).

Teddy Kennedy was considered a serious candidate for president even after he drunkenly drove his car into a pond, drowning a female assistant, and left the scene of the accident. The Trump video from eleven years ago was tawdry and contemptible, as he has acknowledged, but has nothing to do with being president.

The solid phalanx of the anti-Trump press clangorously ululated and screamed that he was a brutish monster too deformed for a zoo but too uncivilized to be loose in society. The crescendo was earth-shaking and the commentariat ranged from almost incoherent moral damnation to unctuous head-shaking, as if contemplating the most shocking electoral disqualification since Vice President Aaron Burr killed Alexander Hamilton in a duel in 1804.

The point was not what Trump said, since such parlance, unfortunately, is routinely uttered by scores of millions of people, including a sizeable number of women, but the confirmation it was deemed to provide of his feral coarseness and temperamental and intellectual unsuitability to being president. All heterosexual men have a sexual interest in women, which is generally reciprocated. It isn’t the “objectification of women,” it’s sex, and if Megyn Kelly thinks she would hold her present position if she weren’t gorgeous, she’s mad.

The Clintons notoriously do anything to win, and are still smarting under Mr. Obama’s stealing their party out from under them eight years ago by persuading the ex officio delegates that even though Mrs. Clinton won the primaries, Mr. Obama should be nominated to break the de facto ban on electing a non-white president. Their glee at this tape disclosure was unseemly and premature. Like Richard Nixon, so outraged at the likely theft from him of the 1960 election by the Kennedys that he became too tolerant of “dirty tricks” when his time came round again, Mrs. Clinton in the Sunday debate pressed the issue of the Bush-Trump video.

No one in the history of these presidential debates was facing the pressures that were on Donald Trump on Sunday night; the Republican-party chairman, Reince Priebus, the speaker of the House, Paul Ryan, and 2008 presidential nominee John McCain all fled on foot from the nominee into the tall grass. Even the Wall Street Journal waffled badly. Mr. Trump’s vice-presidential candidate, Mike Pence, was non-committal, like Gerry Ford after the (innocuous) “smoking gun” of 1974.

Mr. Trump was being widely urged to withdraw, and his campaign was imploding. He apologized for his remarks, said he was ashamed and embarrassed by them, and then counterattacked against the moral shortcomings of the Clinton family, contrasting his words of 11 years before with Bill Clinton’s deeds as president. Round one was a draw, but round two was the opening, by Mrs. Clinton’s imprudent aggressiveness about other ethical matters, to enable Trump to roll out the Hillary Clinton legal vulnerabilities.

Once Trump had neutralized the video and stabilized his position, he fired a torrent of high-explosive ordnance on legal subjects: Mrs. Clinton’s ignoring a congressional subpoena and deleting 33,000 e-mails, the sale of government favors by both Clintons, the sleazy conduct of the Clinton Foundation, her likely perjury about the e-mails in particular (as the director of the FBI strongly implied), and her failure to answer 600 requests for help from the ambassador in Libya, whom al-Qaeda murdered eventually, while Secretary of State Clinton slept.

The point to which this campaign was always destined was finally reached: The Democrats had thrown the kitchen sink at Trump the woman-hating, Muslim- and Mexican-baiting egotist vulgarian, and he had replied to Clinton the crook, perjurer, enabler of the degrading philandering of her husband, steeped to her eyeballs in the corruption and incompetence of the last 20 years of failed American government. There is more truth to Trump’s charges than to Clinton’s, and Trump could generally answer her charges and she did not really respond to his.

They recurred throughout the night and she had no serious refutation of the fact that if American prosecutors showed their customary ferocity, she would be cooked. The nature of the Clinton campaign, based entirely on attacking Trump, exposes its inability to try to justify Mrs. Clinton’s record or argue for the reelection of the Democrats. In the words of the New York Sun’s Seth Lipsky, it is “the bonfire of the hypocrisies.”

If Trump can spend the last month of the campaign showing some dignity as he focuses on policy issues and making regular but not excessive references to his theory that Mrs. Clinton is running for the White House to avoid the jail house, he can still win. The venomous tone of the campaign among the entourages is more disturbing than the mud-slinging between the candidates. There is, after all, plenty of mud to sling, both ways.

The self-justification of some of the intellectual conservatives who have defected to Mrs. Clinton will cause durable fissures. In this election, Mr. Trump, though a moderate, and despite his stylistic lapses, which need hardly at this stage be highlighted, is the only quasi-conservative there is, and Mrs. Clinton, though she is a capable and formidable woman, will flatline the economy buying votes for the public sector and will enthrone political correctness. Even in the debate on Sunday, when prodded, she declined to mention Islamist terror.

The largely neoconservative intellectual Right has led even the Clintonians and defecting traditional conservatives in denouncing Mr. Trump as a primeval, knuckle-dragging monster, repulsive in every detail. As they toil for their ancient Clinton foes, they think that they are saving the integrity of their cause — in this case, thoughtful conservatism. They bewail the acceptance of Mr. Trump by other, allegedly less principled conservatives.

They have read themselves into oblivion. Because Norman Podhoretz and Irving Kristol came quickly and cogently from the soft left to the Reagan right, where they were graciously received, and blended well with the such traditional conservatives as Bill Buckley and even such paleo-conservatives as Pat Buchanan, they earned some of the stardom of the great Reagan victories. Whichever party wins this election, the heirs of the Reagan intellectual Right who have noisily endorsed Hillary as the lesser of evils will be wearing sackcloth and ashes and speaking inaudibly in the wilderness for a long time.

To the Democrats, they are useful idiots; to the Republicans, they are deserters in battle, turncoats. As Laura Ingraham said after the debate on Sunday, “They will go back to their think tanks and devise policies that will never be enacted unless those of us who are trying to defeat Hillary Clinton are successful.” Those of the conservative intellectual Right who have rallied to Mr. Trump, with reservations noted, and those who have sat it out discreetly, will have the task of rebuilding the intellectual Right. It will not be easy under either scenario.

It is good to remember that Donald Trump is not a monster and that Hillary Clinton is not a witch, and both surely would be better than the last two presidents, who by their failures have brought on this very nasty campaign. The election is now a bouncing (American) football and anything could happen.

cbletters@gmail.com. From the National Review.