What did Donald Trump do today?

He declared "tremendous success" in an election where his party lost between 30 and 40 seats in the House.

Trump's first public reaction to the news that the GOP had suffered a shellacking in the House was this tweet:

Of course, Trump is entitled to his opinion—but by all accounts, this isn't his actual opinion. Instead, he is furious, and blames outgoing Speaker Paul Ryan. (Congressional Republicans blame him right back.)

Trump's private fury is understandable, if misdirected. Democrats with subpoena power—particularly on the House Intelligence Committee, which until now has been chaired by a close Trump ally—pose a substantial legal and political threat to Trump.

Why is this a problem?

• With any other president, it wouldn't be. But in this case, it's hard to rule out the possibility that Trump, for all his initial anger, now genuinely believes what he is saying.