After declaring a national emergency to get his wall at the US-Mexico border on Friday, President Donald Trump took a little time on Twitter to mock his Democratic critics — and Mitt Romney.

The tweet features a video of Trump’s State of the Union last week, with REM’s “Everybody Hurts” playing in the background, and shots of various Democrats — Cory Booker, Elizabeth Warren, Kamala Harris, Alexandria Ocasio-Cortez, and more — looking sad while they watched Trump speak. There is also a cut to Romney, who’s at times critical of Trump.

The video is credited to @Carpedonktum, a pro-Trump meme-maker — making it even weirder, since presidents usually don’t promote random Twitter accounts’ content.

Sure, this is funny — if, say, The Daily Show or Stephen Colbert does something like it.

But for the president to tweet it, it’s alarming. In the past, presidents have tried to keep at least a bit of an appearance that they respected and were willing to work with the other party. With his tweet, Trump is doing nothing of the sort; he’s just mocking his Democratic rivals.

It’s another example of how strong negative partisanship — or, in conservative parlance, “owning the libs” — has become. On both sides of the aisle, people love dunking on the other team. As American politics becomes more and more polarized, and Republicans in particular move in more extreme directions, this is becoming a bigger problem — one that’s fracturing both sides’ ability to work together to pass legislation and solve problems.

This even showed up in Trump’s State of the Union speech. Peter Baker reported for the New York Times that the initial speech was supposed to promote a more unified, bipartisan message, but Trump tried to edit it to make it meaner to Democrats — because, Baker wrote, Trump was still “stung by his failure to use a partial government shutdown to pressure Congress into paying for his border wall.”

And we’ve seen it in governments’ inability to really function in recent years, with various threats that the debt ceiling won’t be increased and multiple government shutdowns.

All of that may lead to some funny, unexpected tweets. But those tweets are a symptom of America’s broken politics.