What did Donald Trump do today?

He said he believed Vladimir Putin didn't interfere in the 2016 election, because Putin has repeatedly said so.

Trump had a purportedly unscheduled meeting with Putin at a conference in Vietnam today. Afterwards, Trump railed against the "political hacks" and "liars" of America's intelligence agencies. Trump said Putin had repeatedly insisted that Russia did not interfere in the election: "He said he didn't meddle. He said he didn't meddle. I asked him again. You can only ask so many times. Every time he sees me, he says, 'I didn't do that,' and I believe, I really believe, that when he tells me that, he means it."

Trump's declaration that he believes the leader of a hostile foreign power over his own government's finding was not well received.The "political hack" that Trump himself appointed to the head of the CIA, former Rep. Mike Pompeo (R-KS), flatly contradicted Trump and said that the agency's position that Russia meddled in the election has not changed.

Trump later took to Twitter to explain that if people believed that Putin hadn't interfered in the election to help Trump, then Russia would help "solve North Korea, Syria, Ukraine, [and] terrorism." (Russia is allied with the Assad regime in Syria, is violating sanctions against North Korea's government, and is occupying one part of Ukraine while fighting a covert war in another.)

Why is this a problem?

• It's bad if the President of the United States takes the word of a hostile foreign power over his own government.

• A president who has to make a choice between his own political interests and defending the United States against foreign interference cannot govern and should resign.