The first sign of trouble emerged in July, when Donald Trump was speaking at a White House foreign-policy event, The president was whining about the investigations into his various scandals when he had an idea: Trump would try to shift the focus to his predecessor.

“We want to find out what happened with the last Democrat president,” Trump said. “Let’s look into Obama the way they’ve looked at me. From day one, they’ve looked into everything that we’ve done. They could look into the book deal that President Obama made. Let’s subpoena all of his records.”

There wasn’t anything especially notable about Barack Obama signing a book deal after he’d left office; many modern presidents have done the same thing. But Trump suggested there might be something nefarious about the agreement because … well, just because.

Yesterday, he was back at it.

Instead of investigating reports suggesting that Trump is using his presidency to enrich his businesses, Democrats should look at Obama’s book and Netflix deals, the president said. “I have a better idea. Look at the Obama Book Deal, or the ridiculous Netflix deal,” Trump tweeted.

Soon after, Trump published more tweets defending himself from corruption allegations, and he tacked on “Obama Netflix?” as if it were self-explanatory.

It was not. In fact, these pointless jabs suggest Trump doesn’t fully appreciate the nature of the corruption allegations he’s facing.

To hear the Republican tell it, Obama is making money through private-sector deals and Trump is making money through private-sector deals. Why is everyone making a fuss about his alleged self-dealing while Obama gets by without scrutiny?

The answer – and this is important – is that Barack Obama isn’t president anymore. No one can credibly accuse the Democrat of profiting from his office because he doesn’t currently have an office.

The former president is a private citizen, free to do things like write books and produce documentaries for streaming networks. No one outside the Oval Office thinks to complain about deals like these because there isn’t anything remotely controversial about them. The agreements, which were lucrative, were reached after Obama left the White House.

Trump, on the other hand, has faced different scrutiny because his tactics are unrecognizable by comparison. Before taking office, the Republican was accused of perpetrating private-sector frauds – it’s still easy to feel sorry for Trump University alumni – and during his presidency, Trump has been accused of trying to profit from his office in ways no other president has ever even attempted.

I don’t understand what it is about this dynamic that Trump doesn’t understand.