Stephanopoulos, despite his long history of acting as a hyper-partisan Democrat operative pretending to be a journalist, received decent marks from commentators after he kept pressing the president on his mental fitness despite Biden's continued attempts to evade the questions.

But it's not always the questions asked that are key to sound journalism—sometimes it's the follow-up, and I found one exchange to be particularly telling. Stephanopoulos asked Biden more than once whether he would take a cognitive test, to which the president kept flippantly replying, "I take one every day," but at one point, he blurted out something different.

"No, I've already done it," Biden said.

The moment comes at the 1:56 mark:

Stephanopoulos paused for a second, as if pondering—then abruptly changed the subject. "You've talked a lot about your successes in this interview…" he said, completely ignoring what Biden just claimed. But the obvious next question would have been, "Whoa, Joe! Hold your horses. When did you do this?" And "Where are the results, and when will they be released to the people?"