CHICAGO (AP) — More than 3.5 million Illinois residents voted before Election Day, a surge driven by the coronavirus pandemic.

Voters who began filing into polling places on Tuesday morning are weighing in on president, competitive U.S. House races, legislative contests, and more.

At the top of the ballot is a proposed Illinois Constitution amendment changing the state’s flat income tax to a graduated income tax question that takes a larger percentage from wealthy residents.

Democratic U.S. Sen. Dick Durbin is also seeking reelection to a fifth term over four lesser-known challengers. In central and southwest Illinois, Republican Rep. Rodney Davis faces a strong challenge from Democrat Betsy Dirksen Londrigan.