What did Donald Trump do today?

He forgot how to negotiate.

This morning, in advance of a negotiation session with congressional Democrats over a funding bill, Trump tweeted his opinion that nothing would come of it. He also accused Rep. Nancy Pelosi (D-CA) and Sen. Chuck Schumer (D-NY) of being pro-crime, pro-illegal immigration, and pro-tax.

Noting the pointlessness of "negotiation" under those circumstances, Schumer and Pelosi withdrew from the meeting. Trump will need Democrats in the House to vote for a spending measure to avoid a government shutdown. 

Of all the things Trump regards himself as the best at, he holds the skill he imagines himself having as a negotiator in the highest regard. 

So what?

• Getting nothing of what you wanted means you did not negotiate well.

• A president who cannot restrain himself from outbursts even when they immediately work against him is not fit for the job.

• It's bad if a president can't understand that government shutdowns are a big deal.