It’s no longer news per se that the Trump Organization is profiteering from the presidency. Since Donald Trump refused to divest from his business at the start of his term, that’s been inevitable. There’s the massive emoluments scandal of the Trump International Hotel in D.C. There are Trump’s Irish properties, at which he “invited” the vice president to stay, then charged taxpayers tens of thousands of dollars. There was his shameless choice to hold the G7 summit at Trump Doral—a decision so universally reviled that the White House quickly reversed it. One of the arguments the administration offered for picking Doral was that it would allow savings on security. “He’s not making any money off of this, just like he’s not making any money from working here,” insisted Acting White House Chief of Staff Mick Mulvaney. The new Post story shows that was almost certainly false.

New or not, the question remains: Why does a billionaire charge the Secret Service $650 to stay at his property?

The issue is not whether taxpayers should pay for presidential protection. They should, unequivocally. The question is about the cost. As the Post notes, other presidents who allowed the Secret Service to use their properties, including both George Bushes and Bill Clinton, didn’t charge them. None of those presidents owned a for-profit business while serving as president either.

Perhaps only Trump knows the answer to why he’s charging so much. But here are a few theories as to why so rich a man would gouge his bodyguards and constituents.

The president is simply a penny-pinching cheapo. In 1990, Spy started mailing progressively more minuscule checks to rich people to see who would go through the trouble of cashing them. Only two people cashed the smallest checks, for 13 cents: an arms dealer, and Donald Trump. Trump is the kind of guy who, while running a huge real-estate business, routinely stiffed contractors out of four-figure checks. Why wouldn’t he squeeze every cent out of this too?

David A. Graham: Trump’s most shameless act of profiteering

The profiteering is the point (with apologies to my colleague Adam Serwer). Trump’s presidential run was conceived of more as a publicity stunt than a serious policy initiative. He set out to make money, and if winning the election wasn’t really part of the plan, that didn’t mean it didn’t contribute to the ultimate goal.

It’s about defiance. So many of Trump’s actions can easily be explained as trolling, or at least as a kiss-off. If you tell him he can’t do something, he’ll do it. What other explanation is there for announcing, in the midst of an impeachment investigation over abuse of power, that you’ll direct a major international summit to your own resort? Some people will be appalled by the charges, but there’s nothing they can do. When you’re a president, they let you do it. You can do anything.