Each block represents one of the 100 Senate seats. "D#" is a Democratic senator, "I#" is an Independent senator, and "R#" is a Republican senator. They are arranged so that the parties are separated and a majority is clear by crossing the middle. Each block indicates an incumbent senator's actions going into the election. Both independents caucus with the Democrats. Several sites and individuals publish predictions of competitive seats. These predictions look at factors such as the strength of the incumbent (if the incumbent is running for reelection) and the other candidates, and the state's partisan lean (reflected in part by the state's Cook Partisan Voting Index rating). The predictions assign ratings to each seat, indicating the predicted advantage that a party has in winning that seat. Most election predictors use:  These are the election dates for the regularly scheduled general elections. Bold indicates a future date. In these special elections, the winners will serve when they are elected and qualified. Elections are sorted by date then state. In these general elections, the winners will be elected for the term beginning January 3, 2021. All of the elections involve class 2 seats; they are ordered by state. Incumbent Democrat Doug Jones was elected in a special election in 2017, narrowly defeating Republican nominee Roy Moore. Jones is running for his first full term as a senator. Former senator and attorney general Jeff Sessions and former Auburn University football head coach Tommy Tuberville advanced in the Republican primary on March 3 and will face each other in a runoff on July 14. Sessions occupied the seat until 2017, when he resigned to become attorney general in the Trump administration. Defeated in the primary were 2017 Republican nominee Roy Moore, evangelist Stanley Adair, Representative Bradley Byrne, state representative Arnold Mooney, and community activist Ruth Page Nelson. Alabama is one of the country's most Republican states and Jones's win was in part due to sexual assault allegations against his Republican opponent, Roy Moore. Most analysts expect this seat to flip back to GOP control. Jones will face much stronger opposition this time around, facing either former Auburn Head Coach Tommy Tuberville or former senator Jeff Sessions, depending on who wins the Republican runoff primary. Despite Jones’s competetive polling, many in the Democratic establishment see Jones's seat as a lost cause and he has struggled to raise money. One-term incumbent Republican Dan Sullivan was elected in 2014, defeating incumbent Democrat Mark Begich. He is running for a second term. Potential Democratic candidates include Begich, who was the Democratic nominee for governor of Alaska in 2018, and Anchorage mayor Ethan Berkowitz, who was the Democratic nominee for governor of Alaska in 2010.