Transcript for Joe Biden and former President Obama discuss Trump’s handling of COVID-19
And just before we came on the air tonight, the president announcing the Republican national convention in Jacksonville has now been canceled, saying delegates would still go to North Carolina and that the president would still give a speech. Here's our chief white house correspondent Jonathan Karl. Reporter: Recognizing a reality he had tried to avoid. President trump announced tonight he is canceling the in-person Republican convention that was supposed to take place in Jacksonville, Florida. So, I told my team, it's time to cancel the Jacksonville, Florida, component of the GOP convention. And I'll still do a convention speech in a different form, but we won't do a big crowded convention, per se, just not the right time for that. Reporter: Joe Biden has made president trump's handling of the pandemic a centerpiece of his campaign. They released a socially distanced conversation between Biden and president Obama. I don't think he can associate at all. It is hard to fathom anybody wanting to take away people's health care in the middle of a major public health crisis. And offer nothing. Reporter: The president has been attacking Biden by suggesting he is no longer mentally sharp. He's touted his own mental acuity by describing a cognitive test he took more than two years ago. A test designed to detect memory loss. It was 30 or 35 questions, the first questions are very easy. The last questions are much more difficult. Like a memory question, it's like, you'll go person, woman, man, camera, TV. So, it's -- can you repeat that? So, I said, yeah. So, it's person, woman, man, camera, TV. Okay, that's very good. And then ten minutes, 15, 20 minutes later, remember the first question? Not the first, but the tenth question? Give us that again. Can you do that again? And you go, person, woman, man, camera, TV. If you get it in order, you get extra points. They said, nobody gets it in order, it's actually not that easy, but for me, it was easy. They say, that's amazing. How did you do that? I do it because I have, like, a good memory, because I'm cognitively there. Reporter: Canceling the Jacksonville convention is a huge reversal for the president. He really wanted to do that and was clinging to the idea of giving his acceptance speech before a big crowd long after it was obvious to many others that it simply wouldn't be possible. Now, he's looking for other big events to take its place. He announced one today, he said he'll be throwing out the first pitch at Yankee stadium on August 15th, but of course, David, that will also be without a crowd, as baseball is now being played without any fans. Much more to come on that and the speech that he talks about. Jon Karl, thank you again tonight.
This transcript has been automatically generated and may not be 100% accurate.