Donald Trump announced Monday that he wouldn't be holding a press conference this week to explain how he'll be separating from his businesses after all, despite his promise to do so. Now, his campaign says, it'll happen some time next month. Call me crazy, but I'm guessing that when next month rolls around, it'll get delayed again — should anyone bother to ask, which they may not. Kind of like Trump's tax returns, which we're never going to see.

It's a small example, but of a larger genre, wherein Trump does or says something (or declines to do something), people respond, "How does he think he can get away with this?" and then, lo and behold, he does. So why is it that he's able to do things no other politician and no other president can do, and never seem to pay a price?

The answer lies in the very idea of paying a price, and the unspoken assumptions that undergird it.

Let's say you're the president-elect, and you know that previous presidents have divested themselves of their financial holdings or put their investments in a blind trust. But you don't want to do that — after all, you've spent your entire adult life building this beautiful company, really top-notch, the best. What are you going to do, sell it off? What happens after your presidency is over? You're not going to retire to a ranch. You're going to be back in the game, making deals, bigger than ever. So you decide to let your kids run it while you're away. Sure, you're still the one cashing the checks, and the opportunities for foreign interests and governments to curry your favor by lining your pockets are enormous. But what's to stop you?

To outside observers, this looks utterly appalling. But it makes clear that there are only three real constraints on a president's behavior — and Donald Trump is essentially immune to all three.

1. Legal restraint. As Trump is fond of pointing out, the president is exempt from most of the laws covering conflicts of interest, which means he can't be forced to divest himself of his holdings. That doesn't mean he's immune from prosecution for outright bribery, but that would be awfully hard to prove, especially if we're talking about a situation where a foreign government subtly directs money his way through a third party, like a developer who gives Don Jr. and Eric extremely favorable terms on a deal to license the Trump name to a hotel.

Trump is still covered by the Emoluments Clause of the Constitution, which bans payments from foreign governments. And some have argued that he'll be violating it as soon as he takes office, since his Washington, D.C., hotel is encouraging foreign diplomats to stay there when in the nation's capital, which means more money for Donald Trump. But the only path to accountability for that kind of violation is impeachment, and the chances that the Republican Congress would impeach a Republican president are approximately zero.

2. Political restraint. This is what holds most politicians to the straight and narrow, keeping them from doing things that are unethical or just look bad, but which aren't actually illegal. Trump, however, has learned by now that there's almost nothing he can't get away with. After all, during the campaign he said racist things, encouraged violence at his rallies, had it revealed that he doesn't pay taxes and that his "foundation" is essentially a scam, and was caught on tape bragging about sexual assault — and he still won. The lesson he surely took from all that was that he can get away with pretty much anything, no matter how much criticism he gets in the short term.

He also knows that Republicans, who are eager to get on with cutting taxes for the wealthy, removing regulations on Wall Street, restricting abortion, and shredding the safety net, are not inclined to make him pay a price for what he does. As long as they stand behind him, any controversy looks to the public like just one more partisan squabble, which he'll be convinced he can ride out. He also knows that it will be almost impossible for him to lose the support of his base no matter what he does. As he said during the campaign, "I could stand in the middle of Fifth Avenue and shoot somebody, and I wouldn't lose any voters, okay?" And he was right.

3. Moral restraint. Every ordinary politician has some line they won't cross, not just because they're worried that they could face legal consequences and not just because it might damage them politically, but because their own sense of morality forbids it. Where is that line for Donald Trump? The president-elect is a man who reportedly cheats small-time contractors, who allegedly walks in on teenage girls in their dressing rooms, and who advocates killing the families of suspected terrorists. While he presumably has some moral limits, they have not yet made themselves known.

With none of these restraints operating on Trump, he knows that his freedom to upend established norms, to court scandal, even to use the presidency to get rich, is almost without limit. When he ran for president, his supporters were thrilled by the fact that he wasn't like ordinary politicians. Now we're discovering the full measure of what that means.