Donald Trump explained very clearly at Wednesday morning’s press conference why he won’t release his tax returns, thus leaving the public entirely in the dark as to who may or may not be paying him off: “I won.”

It’s as good an explanation as any. Norms are important in politics and government. But norms get a fair amount of their bite from fear. Fear that if you break them, you’ll come in for damaging criticism and lose public support. But while there probably was a public opinion backlash to Trump’s norm breaking (he was very unpopular on Election Day), the backlash wasn’t enough to cost him the race.

To Trump, winning retroactively justifies everything that came before, and the fact that his win was so unexpected will give him confidence that future taboos can be shattered without cost. This was evident in his behavior long before he entered the political arena.

Business norms say that if you hire someone to do some work for you, you ought to pay them. Trump doesn’t follow those norms. He stiffs contractors everywhere he goes and is happy to wade into litigation rather than pay, knowing that many people can be bullied into accepting less than 100 percent of what they are owed to avoid high legal bills.

Before Trump became a major political figure, I would have thought you couldn’t practice business this way because nobody would work for you. But Trump just moves on to newer places like his brand new one here in DC*, and DC-area contractors are learning what contractors in Atlantic City learned long ago — Trump doesn’t pay up. He defaults on his debts, rips off his shareholders, and defrauds the students at his fake university.

Trump was able to keep making more and more money and becoming more and more famous acting this way, and so he did. By the same token, all his political norm breaking — from his bizarre tweets to refusing to release his tax returns to suggesting Ted Cruz’s father was involved in JFK’s assassination — didn’t derail, and may at times have helped, his election. He’s going to do what he’s going to do, and the reality is he’s right: He won.

But what comes next, in ways Trump may not realize, is different. Lots of presidents have won elections. What they’ve generally found is that the United States is not a plebiscitary dictatorship. The presidency is a powerful office, but its powers are shared with Congress, and to a considerable extent, you can only do what Congress lets you get away with.

The GOP is giving Trump a pass on conflicts of interest

The reason Trump doesn’t need to release his tax returns, or resolve the financial conflicts of interest inherent in his ownership of the Trump Organization, or explain his thinking about Russia clearly is that Republicans haven’t made him.

Congressional Republicans know how to play hardball if they want to.

It would have been trivially easy for the Senate Foreign Relations Committee to refuse to schedule confirmation hearings with Rex Tillerson until its members got to have a chat with the president-elect about Russia.

House Government Affairs Committee Chair Jason Chaffetz has been fanatical about Hillary Clinton email investigations but simply chooses not to hold hearings on Trump’s conflicts of interest.

Congress could amend the statute governing executive branch conflicts of interest to extend coverage to the president.

Nothing along these lines has happened for two reasons. First, congressional Republicans seem to have uniformly reached the conclusion that the political costs of fighting with Trump exceed the political risk that they will end up being dragged down by his corruption when scandal erupts. Second, congressional Republicans seem to have universally reached the moral judgment that preventing the wholesale corruption of the federal government isn’t particularly important in the grand scheme of things.

Winning is easy; governing is harder

What’s less clear is what’s going to happen when Trump finds himself getting into territory that congressional Republicans do care about.

At another point during the press conference, Trump said the federal government should use its purchasing power to negotiate lower prescription drug prices. He said this as if he were the first person in history to think of it, but there is in fact a controversy over this that’s been running in Washington for decades. It reached a head back in 2003, when George W. Bush and congressional Republicans rather controversially stole a Democratic proposal to add a prescription drug benefit to Medicare but then included a legal bar on bulk price negotiations. The resulting legislation passed over Democratic objections, and liberal Democrats have been promising for years to overturn it.

Barack Obama campaigned on this idea in 2008, only to abandon it as part of a bargain to get the pharmaceutical industry to support the Affordable Care Act, only to reembrace it in his second term (and then seem to back away from it in a lame-duck Vox interview, but that’s another story).

All of which is to say that if Trump is serious about doing this, he will probably find plenty of Democratic votes for it. But this is a popular idea that Republicans have been blocking for years. They are blocking it because they think it would be a bad idea (reduced incentives for pharmaceutical research), and they are blocking it because the pharmaceutical industry has a lot of money and clout.

If Trump is satisfied by just musing aloud about this while not actually changing anything, Paul Ryan will be happy to ignore him.

But if he actually wants to do it, he’s going to have a big fight on his hands. And while to an extent his favored tactic of roasting congressional Republicans with his tweets could work as pushback, they have some powerful weapons in their hands. After all, the choice to turn a blind eye to Trump’s ethical lapses is a choice that, in practice, the GOP has to reaffirm anew every single week. If Trump asks for things Republicans don’t want to do, they won’t happen. If Trump punches his party hard to try to make them do those things, they can punch back. Governing is hard.

For now, though, congressional Republicans seem convinced that Trump will stick to tax cuts and deregulation as the core of his agenda — with protectionist tweets serving more as a theatrical sideshow than as the dawn of a new heterodox approach to policymaking. As long as that’s the case, they’re willing to hold up their end of the bargain. But that’s the real reason Trump doesn’t need to disclose anything — it’s not that he won; it’s that his allies in Congress think letting him get away with it is the best way for them to get their way on policy.

Correction: an earlier version of this article said there was no Trump Hotel in New York, which is not the case.