Donald Trump would be an absolute disaster of a president — so bad it's almost impossible to grasp.

But allow me to try.

First, this birther business. Trump got his start in national politics by peddling the racist conspiracy theory that President Obama was not born in the United States. Trump attempted to memory-hole that history last week with more lies, blaming the whole thing on Hillary Clinton and claiming credit for clearing it up. But it must not be forgotten that the whole thing is a transparent smear on the first black president, created by and for outright racists, and without which Trump would not be the Republican nominee for president today.

Second, his business record. Trump's business career is his major — indeed only — argument for why he is qualified to be president, so it deserves close examination. In the reporting on his various business ventures, one consistent pattern emerges: On traditional notions of business or investing, Trump is mediocre to poor. But he is very good at enriching himself at the expense of others.

Trump's real estate development record is mixed at best, and several forays outside property ownership and management — be it education, food, or gambling — all ignominiously collapsed. At bottom, the Trump business formula is simple: Borrow a ton of money, invest in real estate during a boom, cash out the equity to a protected location, then declare bankruptcy after the market turns. This is an effective strategy when conditions are right, but it is purely taking advantage of external conditions. No business is really happening. It's pure parasitism. (It's unclear whether Trump even understands this is his strategy.)

Trump is, however, almost preternaturally talented at two things: self-promotion, and structuring contracts and deals so as to extract the maximum benefits for himself at the lowest risk. These sometimes butt into each other, as Trump's unquenchable desire for flattery and media attention overpower his weasel sense for the contract, or cause him to surround himself with dimwitted yes-men instead of intelligent advisers.

Third, domestic policy. Trump does not have a remotely comprehensive policy platform. He clearly has no interest in building one. He clearly is unable to build one.

Trump constantly (and inadvertently) reveals his staggering ignorance of the most basic facts of government and recent history. Trump didn't know that Russia had annexed Crimea. He didn't know what Brexit was. He didn't know that the Trans-Pacific Partnership does not include China. He is very obviously a guy who gets his news from half-watching cable TV and the racists in his Twitter mentions.

When he does talk policy, his positions shift on a daily basis: First he was against huge tax cuts for the rich, then he was for them even more than his primary opponents. First he was against raising the minimum wage, then he was for it, then he said it should be up to the states. First he said Japan should have nuclear weapons, then they shouldn't. And on, and on, and on.

When NBC News attempted to compile a list of every Trump flip-flop, they came up with 117 major changes in positions — and that's likely an underestimate, since it was published a few days ago. Even on his signature issues — the border wall that Mexico is supposedly going to pay for, and banning all Muslim entry into the United States — Trump is all over the place. One day it's round up and deport all 11 million unauthorized immigrants and ban Muslim immigration, the next it's a path to citizenship, and only partial Muslim restrictions, then back to mass deportation.

It's unclear whether Trump's constantly shifting positions are the result of trying to obscure past views, or merely the fact that Trump can't pay attention to any one thing for more than five minutes at a time. Just read the transcript from one of his rambling, disjointed speeches.

Insofar as one can discern any sort of domestic agenda through his blizzard of nonsense and rapidly shifting positions, Trump's favorite things are discriminating against Latinos and Muslims. The political forces behind him include a sizable fraction of straight-up white nationalists.

On women's issues, too, his personal record is grotesque. In his family life, he has boasted that he has never changed a diaper in his life and that he expects his wife to do all the child-rearing while he merely pays for things. He once said that breastfeeding is "disgusting," and has an extremely unsettling habit of mentioning how sexually attractive he finds his daughter. He reportedly treated his Miss Universe and Miss USA contestants like crap. He has unleashed a slew of sexist attacks on other women, from Rosie O'Donnell to Carly Fiorina to Megyn Kelly.

His policy on women's issues is virtually absent. Now, under the influence of his daughter, he did release a paid leave "plan," which calls for a pitiful six weeks of paid maternity leave, to supposedly be paid for by reducing fraud in unemployment insurance (his funding mechanism is about 90 percent short of the needed total, at best). But this is a fig leaf, nothing more.

God only knows what sort of laws the Trump administration — which would be certain to enjoy large Republican majorities in Congress, as well as GOP control of something like three-quarters of state governments — would produce. But if I had to guess, it would be some combination of state bigotry and Paul Ryan's budget. Put Muslims in camps, plus massive social service cuts for minorities.

Fourth, civil liberties. Trump's obsession with media attention is only rivaled by his intolerance for criticism in the media. He's gotten more coverage than anyone in the history of politics, but promises to "open up" libel laws so he can more easily sue news organizations who give him negative coverage. Like his prominent supporter Peter Thiel, Trump wants a press composed of nothing but wall-to-wall Baghdad Bob-style lickspittles, and as president, he would have access to the dragnet surveillance apparatus that could make that a reality.

Over and above his threats against a free press, Trump's campaign has been the most overtly violent in living memory. His rallies have seen a steady stream of violence since early in the primary — most recently, a Trumpist socked a 69-year-old woman on oxygen right in the face. Trump has incited and encouraged this violence, telling his rallies that violence is acceptable, refusing to condemn such behavior when journalists ask, and even saying he might pay the legal bills for a man arrested for allegedly assaulting someone at a rally (though Trump, as usual, later insisted he had done no such thing).

Trump's campaign has accomplished the greatest legitimization of political violence since white supremacist "Redeemers" violently overthrew democratically elected Reconstruction governments in the 1870s. He represents a movement of proto-fascism that will probably endure long after he is gone.

Fifth, foreign policy. Trump generally claims to be an anti-interventionist. He says that he was against the Iraq war and the Libya intervention. He is straight-up lying about both. A 2002 interview and a 2011 video from Trump's Facebook page (that was still up when he was making the Libya claim, incidentally) demonstrate that he was in favor of both actions at the time.

One might argue that better a Johnny-come-lately peacenik than a current warmonger, but even setting aside the problem of trusting someone who is constantly lying, Trump is just completely not credible as a peace candidate. He promised AIPAC that he would tear up the nuclear deal with Iran — and that Iranian ships which mildly provoke U.S. naval forces in the Persian Gulf with rude gestures should be "shot out of the water." This would almost certainly result in a shooting war with Iran — which incidentally is fighting against ISIS on the same side as U.S. forces.

Trump's foreign policy might well be corrupt. As Kurt Eichenwald details in Newsweek, Trump is involved in dozens of shady business and real estate deals overseas through the Trump Organization — in South Korea, India, Turkey, the United Arab Emirates, Azerbaijan, Russia, Ukraine, and elsewhere. It would be almost impossible for Trump to conduct foreign policy without hitting conflicts of interest. Not that he would care about such things; instead, he would almost certainly attempt to leverage the power of the presidency to secure more lucrative deals for himself. Profit and self-promotion are the only consistent notes in the life story of Donald Trump.

Finally, temperament. All of the above factors tie directly into Trump's personality. Like his idol Vladimir Putin, Trump is an egomaniacal bully who is totally intolerant of criticism — so much so that he puts a clause forbidding it forever into his campaign volunteer contract. He surrounds himself with sycophants and lapdogs — Chris Christie knew that the best way to ingratiate himself to Trump was humiliating, obsequious deference.

Everything we know about Trump suggests he'd abuse the power of the presidency to settle personal vendettas, enrich himself, and get the United States in dangerous spats with half the nations on the globe. He is very obviously the kind of thin-skinned maniac who would be constantly looking to demonstrate his masculinity and prowess by pushing other countries around with the world's most powerful military.

Scholars argue that democracies are more stable than monarchies in part because they can survive a bad leader or two. But the flexibility is not endless. Donald Trump might well bend the rickety American constitutional system past the breaking point. Don't let him.