Joe Biden Tells George Stephanopoulos He Won't Do Cognitive Tests

Joe Biden says there's no need for him to take a formal cognitive test to prove his abilities to lead the nation ... claiming his involvement in daily world issues should be enough to show he's up for the gig a second time around.

In a full ABC special Friday, Biden fought hard to defend himself from his rough June 27 debate performance ... explaining to George Stephanopoulos he was just down with a serious bout of cold -- so bad he took a COVID test.

While he says he didn't end up having COVID, Joe insisted exhaustion also played a part in his performance. He also admitted he didn't listen to his instincts in terms of preparing -- so looks like a variety of things contributed to his bad night.

But as for the longstanding concerns about his mental state, Joe was adamant a great team of doctors travel with him everywhere and constantly evaluate him. He said the consensus was that he's still in good health ... so he sees no need to undergo a full medical evaluation.

George wasn't buying it ... firing back with questions about him being behind in the Presidential race. But Joe told him it was the same case back in 2020, and he still won ... and was planning on doing the same thing this year.