Worst moment

Mr. Biden was on the receiving end of the most memorable attack in the debates so far, when Senator Kamala Harris of California confronted him over his comments about segregationist senators and his record on busing.

Experts say

“There are very few candidates who are able to connect on an emotional and personal level with voters the way Joe Biden typically does. But in that exchange with Harris, when she looked at him and gave an intensely personal anecdote, he fell far short of doing so.” — Mo Elleithee, former spokesman for the Democratic National Committee, on the first debate

“@JoeBiden finally played the card he should have played in the last debate when @KamalaHarris challenged him on race. @BarackObama vetted his record and nominated him for Vice President.” — David Axelrod, former chief strategist for President Barack Obama, on the second debate