Biden emerges from quarantine to meet with black activists, taking a knee in solidarity. He promises a major speech and economic plan in coming weeks, seeking a contrast with Trump.

“As a predominantly white organization, we have an obligation to be fully and visibly committed to the fight against systemic racism,” one group said.

The attorney general said in an interview that “it’d be very hard” to stop foreign governments from submitting phony ballots. Election officials said it would be virtually impossible for such fraud to succeed.

President Trump, for his part, has been reluctant to adjust his approach despite the widespread unrest. He has continued to inflame rather than soothe tensions.