Early 20th century modernism ignored classical rules of expression. But late 20th century postmodernism blew up those rules altogether.
Barack Obama was a modernist candidate. He turned out vast numbers of young and minority voters, mastered new social media, and in 2008 overturned the old-guard Democratic furniture such as Hillary Clinton.
In contrast, Donald Trump has simply destroyed normal politics. Unlike President Obama with his record Wall Street fundraising of 2008 and 2012, Mr. Trump has raised almost no money. He ignores endorsements from political kingpins. Mr. Trump has organized no serious voter registration drives. His convention was bizarre, showcasing his kids instead of party bosses and special-interest groups.
How about internal polling? Mr. Trump seems to have none.
Sophisticated opposition research? Zilch.
Standard talking points? Not so much.
Teleprompted speeches? Mr. Trump prefers ad-hoc stream of consciousness.
Candidates are supposed to avoid the pitfalls of press conferences as much as possible — and prep for days when they are obligated to give them. Not Mr. Trump. He thrives on unscripted rants to the press without much worry about what he says.
Candidates dislike and fear reporters, and so seek to flatter them. Mr. Trump openly insults them and occasionally kicks them out of his press conferences.
Modern politicians generally avoid getting pulled into nasty, lose-lose fights. Mr. Trump welcomes brawls against all comers.
Hillary Clinton has taken huge quid-pro-quo contributions from rich people as she damns the influence of big money in politics. Mr. Trump cannot seem to find any big donors. He trashes crony capitalist insiders on the grounds that he used to be one himself.
Traditional politicians such as Mitt Romney were perfectly groomed and rarely appeared without tailored suits. Modernist politicians such as Mr. Obama like to be photographed on the golf links appearing young, hip and cool, wearing shades and polo shirts.
But Mr. Trump defies both traditional and nontraditional tastes by wearing loud, long ties, combing his dyed-yellow hair over a bald spot, and tanning his skin a strange orange hue.
Politicians attack each other while faking politeness. The coolest do it with nuance. Not Mr. Trump. He uses taboo words like “liar” and “crooked.”
Modernist candidates voice platitudes about border enforcement. But only a postmodern one would demand that Mexico pay for a wall.
For a modern politician, a gaffe is an inadvertent truthful statement. For a postmodern Donald Trump, the only gaffe imaginable is to stay silent.
All presidential candidates court top party officials, former presidents and defeated rivals, and seek praise from newspapers and magazines.
When Mr. Trump either does not win such approval or is ridiculed by major media and those in his own party, he pouts, saying his critics are losers without much clout anyway.
The bible for modern politicians is political correctness. They must defer to every imaginable hyphenated group and “community,” employing euphemisms or self-imposed censorship while sidestepping race, class and gender land mines as much as possible.
Again, not Mr. Trump. He says what he pleases. If he blows himself up with a politically incorrect outburst, what is left simply flows back together, as if he were some sort of political version of the Terminator.
Mr. Trump was supposed to fade last summer. His crudity was said to guarantee that he would lose Republican primaries.
Then, pundits said Mr. Trump’s vulgar style of primary campaigning would not translate well to the general election.
Now, even seasoned politicos confess there are no rules that apply to Donald Trump. He just keeps shouting that things are getting worse and no one will admit it.
We live in a politically correct age in which Mr. Obama is unable or unwilling to mention radical Islamists as the terrorists who have killed hundreds in Europe and the United States.
No one dares suggest that the more than 300 sanctuary cities in the United States are a rebirth of the illiberal and neo-Confederate idea of nullification of federal law. Black Lives Matter is idealized as a civil rights group despite the chants at its protests about violence toward police.
Doubling the national debt to nearly $20 trillion in just eight years is regarded as no big deal.
The public is growing tired of two realities: the one they see and hear each day, and the official version that has nothing to do with their perceptions.
Mr. Trump comes along with a ball and chain and throws it right into the elite filtering screen — and the public cheers as the fragile glass explodes.
If most politicians are going to deceive, voters apparently prefer raw and uncooked deception rather than the usual seasoned and spiced dishonesty.
Will Mr. Trump fade in August, implode in September, self-destruct in October — or win in November?
No one knows. There are no longer rules to predict how a fed-up public will vote. And there has never been a postmodern candidate like Donald Trump.
• Victor Davis Hanson is a classicist and historian at the Hoover Institution at Stanford University.