What did Donald Trump do today?

He once again said it was a crime to make fun of him.

For years now, Trump has occasionally launched into spontaneous discussions of what, for him, is the fascinating subject of the catapults that help planes launch from aircraft carriers. (Returning to familiar, well-worn pieces of "patter" is a common coping strategy for people, like Trump, who struggle to articulate their thoughts or control their emotions.) In particular, he feels strongly, to the point of obsession, about the need to return to steam-driven systems rather than use the modern EMALS system—or as Trump calls it, "magnets."

There have been presidents who were naval engineers, but Trump is not one of them, which may explain why he appears to genuinely believe that the "magnets" will not work if they get wet, among other falsehoods. For actual experts, the matter is settled and the benefits of faster launches, less aircraft maintenance, and the ability to launch a wider variety of aircraft are decisive. So when Trump once again promised, seemingly off the cuff, to issue an executive order requiring that aircraft carriers "go back to steam," it was no surprise that the Navy refused to comment.

On Thursday, Seth Meyers did a few jokes about Trump's supposed engineering brilliance on his late-night show—

—which prompted Trump, who seems to comment on Meyers a lot for someone who never watches him, to say that it was "PROBABLY ILLEGAL!!!" for Meyers to make fun of him.

In reality, because of the rights guaranteed by the First Amendment,  it is not illegal in the United States of America to be "ANTI TRUMP" or anti- any American politician, or to say that you are, or to make fun of them.

This isn't even the first time this week that Trump has ranted on social media about how it should be illegal to mock him, and ironically, the second part of Meyers' monologue was about how Trump said it was "almost treasonous" to point out how little he'd accomplished on his recent trip to Asia. Meyers almost seemed to anticipate Trump's rant, saying, "The point is, Trump thinks if you say something mean about him, that's treason. Which is why on this show, I only do constructive criticism. Which I'm being told is also treason."

Why does this matter?

• No matter how many times he says otherwise, it's not illegal to make fun of Donald Trump. 

• One way presidents can avoid people making fun of them for stupid opinions is not to share opinions on subjects they don't know anything about.