 For his part, Donald Trump issued a stream of exaggerations and untruths, but he was quick to capitalize on Mr. Biden's weakness. At one point, the former president said, quote, I don't know what he said at the end of that sentence. I don't think he knows what he said either. Aaron Regenberg is a progressive Democrat and a former Rhode Island state lawmaker who supported Mr. Biden before last night. We reached him in Providence, Rhode Island.