What did Donald Trump do today?

He ignored his own government when it told him he'd been tricked by Iran.

On Saturday, Trump took to Twitter to sound the alarm about an Iranian ballistic missile test. Iranian state TV had reported the launch, and it was picked up by American TV news, which is presumably where Trump heard about it. Today, US officials confirmed that no such test took place, and that the Iranian news report was a fake, replaying footage of an unsuccessful attempt from January.

As of this post, Trump has neither deleted nor otherwise retracted his tweet from Saturday, on Twitter or in any other medium. 

Two of the constants in Trump's life are a belief that he is a skilled negotiator, and a hatred for former President Obama. As such, the talks carried out in cooperation with five other nations during the Obama administration, which led to the current Iranian nuclear deal, have become an obsession for him. This in turn may explain why he is reluctant to correct himself. But it is also possible that he was never informed about his mistake, or that he was and has already forgotten.

So what?

• Presidents shouldn't fearmonger, and if they do they should do it about things that actually happened.

• It's bad if a president uncritically believes the propaganda of hostile nations.

• Being unable to admit any mistake, no matter how small, is not a sign of good mental health.