Then: He borrowed a long speech from British politician Neil Kinnock but failed to attribute it in the Iowa debate in 1987. Biden withdrew during the resulting controversy. Now: He called Obama, who is black, "clean" and "articulate" in a clumsy compliment.
Can he avoid cringe-inducing mistakes on the world stage if elected president? "Yes," was his one-word response in an MSNBC debate in April.
This week, Biden's smoothly delivered talk went over well with the Rotarians, by their own description a heavily Republican club.
"Very down to earth, right to the point, and I'm a Republican," says Linda Grugnale, 51, an unemployed sales rep. "He was different, and I like that. He has a plan. If someone else had a plan, maybe everybody would listen to their plan, too, but there is no plan."
Biden "combines the depth of experience with refreshing candor, and what could be better than that?" says Tina Andrade, 60, a hospice development director. "It's one thing to be candid, but to be candid when you know what you're talking about, that's great."
But she's planning to vote for Clinton. "The country is in the worst position it's ever been in and needs someone brilliant, and I believe that's her," Andrade says. "If there's an answer, she's a very strategic thinker."
Norm Laplante was listening to Biden for the second time. In 1987, he stepped to the podium and amused Rotarians with tales of his vacation until Biden returned.
He is skeptical about Biden's three-state Iraq plan. "I don't think there's any solution," says Laplante, 70, a real estate broker and Republican. "I think the man is trying, but I don't think he has any more idea than anybody else."