Pennsylvania, where Biden was born, will award 20 electoral votes as one of the country’s top prizes. Erie County will help to test whether Biden’s economic message can break through in the Keystone State’s former Democratic strongholds — and others across the Midwest — that gave a Republican political newcomer a try four years ago.

“I really look at Erie County as a bellwether county not just for Pennsylvania, but for counties like it across the United States, particularly the Rust Belt area throughout the Midwest,” said Joseph Morris, chair of the political science department at Mercyhurst University in Erie. “It is just so typical of counties in the Midwest that once had an industrial base that has seen that industrial base evaporate in three decades.”

Erie County will offer one of the better tests in Pennsylvania of how effectively the rivals can tailor their messages to working-class people, according to political observers in the area. With an 87% White population and a lower percentage of college graduates than the country as a whole, the area is home to some of the White working class Trump had success reaching in 2016. Low turnout in the area among people of color — whom exit polls found overwhelmingly backed Clinton in Pennsylvania — also reflects the struggles Democrats had winning over non-White voters in the Midwest in 2016.