For more than a decade, Wisconsin has been among the most polarized and evenly divided states in the country, and the fate of its political candidates has hung on turnout. When Democrats in its two major cities — Madison and Milwaukee — turned out in big numbers, party standard-bearers like Barack Obama and Gov. Tony Evers won statewide elections. But when Democratic turnout in Milwaukee or Madison has been soft, Republicans have prevailed: former Gov. Scott Walker carried the state in three elections between 2010 and 2014, and Mr. Trump won in 2016 by fewer than 23,000 votes out of nearly three million cast.
In Wisconsin’s cities, enthusiasm is high. The poll found 81 percent of voters in the cities said they were “almost certain” to vote, compared with 69 percent of suburban voters and 68 percent of rural voters. These city voters are also far more likely to favor Mr. Biden over Mr. Trump to maintain law and order. The intensity gap, if it is maintained through Election Day, is likely to benefit Mr. Biden.
In Trump-era elections that Democrats have won, there has been a surge of voter turnout in heavily Democratic Dane County, which includes Madison — the state capital and home of the flagship University of Wisconsin campus. In April’s state Supreme Court election, nearly as many votes were cast in Dane County as in Milwaukee County, even though Dane County has less than 60 percent of Milwaukee County’s population.
Justin Lang, a 38-year-old software developer in Verona, just outside Madison, said he had already ordered his absentee ballot to vote by mail for Mr. Biden.
“One hundred percent,” he said, when asked how certain he was that he would vote. “I don’t know that everyone is gung ho about Joe Biden in particular, but there’s a shared feeling across the board that Trumpism is a big problem. And that we need to get in there and vote to repudiate that.”
He added, “Within my social group, that’s going to be a big thing.”
The swing region of the state is the Fox Valley, a collection of small cities and rural areas stretching south from Green Bay. Andrew Fox, 38, an Iraq war veteran from Menasha, a community of 18,000 on the northern tip of Lake Winnebago, said he was not a fan of either major presidential candidate but was inclined to stick with Mr. Trump.