The President has the authority to over-ride the classification.
However, that doesn't change the fact that the President is an idiot and should not have retweeted this.
Right...
shouldn't have tweeted something that had already been broadcast to millions of people.
Confirming classified information that has been leaked is the equivalent of leaking the information.
explain that.
It doesn't take much brains to understand, but in your case I guess I'll have to explain.
When you have a security clearance, one of the things you are told is that you should never confirm or deny classified material. Anybody could be just 'fishing' and your confirmation or denial is the equivalent of disclosing the classified material.
Trump's retweeting classified materials confirmed that material which was otherwise not confirmed.