In Minnesota, Mr. Biden was ahead among suburban voters by 20 percentage points. In Wisconsin, that advantage was just five points.More significant for the former vice president is his strength with seniors, an advantage Democrats did not enjoy four years ago. Mr. Biden enjoys a 12-point lead, 52 to 40, among people 65 and older across the four states and, by overwhelming numbers, they say he would do a better job than Mr. Trump unifying the country, handling race relations and addressing the pandemic.These same voters remain deeply concerned about the virus, with 58 percent of them saying “the federal government’s priority should be to limit the spread of the coronavirus, even if it hurts the economy.” If there is a warning sign for Mr. Biden in the survey below Mr. Trump’s modest growth, it is that many seniors want him to more forcefully denounce the violence that has grown out of the summer’s racial justice protests.By a 20-point margin, 53 to 33, voters over 65 in the four states said the former vice president had not done enough to denounce rioting. And 70 percent of these same voters said crime was a “major problem” in the country.Ellen Christenson, a 69-year-old Wisconsinite, said she voted for former President Barack Obama twice before backing Jill Stein, the Green Party nominee, in 2016. Now Ms. Christenson said she was torn between Mr. Trump and Mr. Biden and “could go either way.”Mr. Biden, she said, had not sufficiently “condemned the violence and the burning.”Originally a supporter of the Black Lives Matter movement, Ms. Christenson said she now felt it had “gone too far,” and she said she “kind of resented” that her workplace recently forced her to take a seminar on microaggressions.