After enduring months of campaign ads, fliers and rallies, Pennsylvanians today will help decide the winner in a long, hard-fought presidential campaign and control of the U.S. Senate next year.

Hillary Clinton has a built-in voter registration advantage over her Republican counterpart, Donald Trump, in Democratic-leaning Pennsylvania, a state that has backed the Democrat in six straight presidential elections.

Pennsylvania’s 20 electoral votes are a key building block in the path to winning the 270 necessary to win the Electoral College. No Democrat has gotten to the White House without winning Pennsylvania since Harry Truman in 1948. George H.W. Bush was the last Republican to win Pennsylvania, where Democrats hold a 4-to-3 registration advantage over Republicans.

Just below Clinton and Trump on the ballot is the hotly contested U.S. Senate race between Democratic challenger Katie McGinty and Republican incumbent Pat Toomey. Toomey is among the most vulnerable Senate Republicans as the GOP struggles to hang on to their 54-46 Senate majority.

The Senate campaign has dominated TV screens, becoming the nation’s most expensive race ever with spending on it passing $160 million.

Meanwhile, voters also will decide whether to change the Pennsylvania Constitution to allow more than 1,000 appellate, county and district judges to remain in their jobs until the age of 75. The current mandatory retirement age is 70.

Also on the ballot are three statewide races for attorney general, treasurer and auditor general.

Democrat Josh Shapiro and Republican John Rafferty are vying for the right to succeed Kathleen Kane as the state’s top law enforcement officer. Kane won a landslide in 2012 to become the first woman and first Democrat ever elected to be attorney general, but she resigned in August after being convicted of abusing the office’s powers by leaking secret investigative information and lying about in a scheme to smear a rival prosecutor.

For treasurer, Democrat Joe Torsella and Republican Otto Voit are running to fill and office that’s also been marred by corruption, since Democrat Rob McCord resigned last year and pleaded guilty to federal extortion charges related to his unsuccessful 2014 gubernatorial campaign.

In the race for auditor general, Democrat Eugene DePasquale is seeking a second term against Republican John Brown.

Two races for seats in the U.S. House are notable.

Democrat Dwight Evans is seeking to become the new member of Congress from the heavily Democratic 2nd District, replacing the resigned and convicted Chaka Fattah. Evans is also seeking a two-year term in the office starting in January. His Republican opponent is James Jones.

The 8th District race is a tossup, between Democrat Steve Santarsiero and Republican Brian Fitzpatrick, who is running to replace his retiring brother, Mike Fitzpatrick, in the seat.

Voters also will decide 228 seats in the Pennsylvania Legislature, although Republicans are expected to maintain their large majorities in both chambers.