Mr. Trump’s repeated calls for voter registration and a robust voter turnout, sometimes near violent, rhetoric fueled by ideological motives versus Mr. Biden’s calls for dialogue and unity toward achieving shared goals.
The intense rhetoric can come at any time of day — or night.
The Clinton campaign, which is approaching the final phase of the general election campaign with a concerted focus on battleground states, has struggled in recent weeks to promote voter registration and turnout efforts.
The Clinton campaign has begun airing a series of radio ads in North Carolina on that theme, for example, and Mr. Trump’s recent focus on voter suppression by Texas officials in recent days has been a reliable way for the campaign to highlight voting efforts it finds offensive and counterproductive.
Mr. Trump raised the prospect of violence at the campaign’s first debate last month when he alluded to the possibility of a candidate being “sucked out by a sucker punch.”
Trump avert debates amid security
Mr. Trump said in September he did not “even know” the number of people watching the debates.
Just how many people tuned in to watch the first debate in Hempstead, N.Y., is in dispute. The Nielsen ratings company said that the audience reached 31.5 million on Sept. 26. According to the Associated Press, the sum number of viewers was reported by organizers to be slightly higher, at 30.7 million.
Ultimately, both campaigns could use the debates to test whether they get more traction than their rivals, raising the specter of an election played out against an empty podium.
It remains unclear whether the conventions and debates have made much difference, with both campaigns continuing to document the kind of lackluster crowds that are still commonplace in major cities.
Clinton staffers point to improving numbers as the campaign gathers speed in swing states. The campaign boasted last week that it surpassed its fundraising goal for October, largely through online receipts that remained viable even after Clinton conceded to Mr. Trump.
— Alexander Burns and Jonathan Martin contributed to this report.