Part of the reason I want to document this period is because in no time at all, we’ll know this is true, but won’t remember the moment when the depths of this man’s ignorance was first uncovered.

I grant that until the election he didn’t have to know about this kind of information. But you think that you could take it for granted that before any call was scheduled, the President of the US would ask for and receive a full, detailed briefing to catch him up on little details like… the foundation of one of the most important parts of the US/Russia relationship.

But no…

Asked by Putin about the possibility of extending the treaty capping U.S. and Russian deployment of nuclear warheads — known as New START — Trump reportedly paused to ask his aides what the treaty was, two U.S. officials and one former U.S. official briefed on the call told Reuters.

He then told Putin it was one of a number of bad deals negotiated by former President Barack Obama and that it favored Russia, before launching into a conversation about his own popularity, according to the sources.

Source: Trump denounced arms-reduction treaty in Putin call: report | TheHill