“cc: bedwetters,” Mr. Ducklo wrote, in a dig at nervous Democrats.
In North Carolina on Wednesday, Mr. Trump appeared to encourage voter fraud, suggesting that people vote twice in order to test the system’s ability to detect when more than one ballot is cast. It is illegal to vote more than once in an election, and Mr. Trump has spent weeks trying to cast doubt on the legitimacy of the election because of the prevalence of mail-in voting.
Three new polls from Fox News in battleground states on Wednesday showed Mr. Biden ahead in Arizona (49 to 40 percent), North Carolina (50 percent to 46 percent) and Wisconsin (50 percent to 42 percent). The survey showed Mr. Biden with a five-point edge in Wisconsin and Arizona on who would better handle “policing and criminal justice” issues, and a virtual tie in North Carolina.
A new Pennsylvania poll from Monmouth University, meanwhile, showed the race tightening, with Mr. Biden’s lead shrinking, from a 10-point advantage among likely voters in a high-turnout election in July to a three-point edge now. His lead in a lower-turnout election shrank to a single percentage point, from seven points in July.
“It looks like some of those attacks, some of those messages that are coming out of the Republican convention about threats to the suburbs, has caused some doubt among some voters,” said Patrick Murray, the director of the Monmouth University Polling Institute.
Pennsylvania is seen as crucial by both candidates. On the same day that Mr. Biden delivered his speech for the Democratic National Convention, Mr. Trump traveled to Scranton, Pa., where Mr. Biden grew up, for his own event. And Mr. Biden chose to go to Pittsburgh to deliver his speech on Monday rebuking and responding to Mr. Trump’s often misleading attacks and trying to turn the question of safety back to a focus on the coronavirus. It was generally well received among his Democratic allies.
Priorities USA, a leading Democratic super PAC, on Wednesday described Pennsylvania as the tipping point state of the 2020 race, and released findings from a private poll of battleground states that showed Mr. Biden with a wide lead on handling race relations but knotted in a virtual tie on policing and law enforcement.
Guy Cecil, the chairman of Priorities USA, who had previously predicted a tightening of the polls as the election neared, described the 2020 race as “just structurally close.”