Oct. 30 (UPI) -- After the race for president and vice president, the highest stakes in Tuesday's election lie in the U.S. Senate, with a possibility that Democrats could retake control.
With 45 seats, plus two independent senators, Democrats need to win four seats to guarantee a majority in the Senate. They would need to win just three if presidential nominee Joe Biden wins the White House, as Kamala Harris would tip the balance as Senate president.
Here are some the closest races.South Carolina: Incumbent Lindsey Graham (R) vs. Jaime Harrison (D)
This race has gotten a lot closer in recent weeks, due to fundraising by Harrison and some eroding support for Graham.
Graham was widely criticized for supporting Amy Coney Barrett's nomination for the U.S. Supreme Court after denying President Barack Obama's nominee in 2016, saying, on multiple occasions that Republicans would never consider one of President Donald Trump's nominees in an election year either.
"You can use my words against me," he said at the time, and "hold that tape" during a television appearance, should such a nomination occur in 2020.
Harrison has made up tremendous ground in polling over the last few weeks and many analysts list this race as a tossup, while some others call it a lean for Graham.
Arizona: Incumbent Martha McSally (R) vs. Mark Kelly (D)
McSally is in a closely contested race with Kelly, a former astronaut and husband of former Rep. Gabrielle Giffords.
Appointed by Gov. Doug Ducey two years ago to complete the term of the late Sen. John McCain, McSally has not followed McCain's maverick, independent-minded strategy -- which famously put him at odds with Trump.
Instead, McSally, a regular Trump supporter, has appeared at multiple rallies for the president and has pinned her hopes on appealing to the right-leaning rural base of the state's Republican voters.
On the other side, Kelly has tried to pick up McCain's maverick mantle and has promised to look for bipartisan solutions.
Demographic shifts and almost 1 million new residents are helping to shift Arizona's partisan leanings. Many of the new Arizonans are from California, a state that's long been solidly Democratic.
Most experts and polling indicate this is a tossup race, or slightly favors Kelly.
Colorado: Incumbent Cory Gardner (R) vs. John Hickenlooper (D)
Gardner, a freshman Republican senator hoping for re-election in a solidly Democratic state, has lost some support for being a Trump supporter.
Six years ago, Gardner flipped the seat by defeating Democratic incumbent Mark Udall by about 40,000 votes.
Hickenlooper, who briefly ran for the Democratic presidential nomination, formerly served as Colorado governor between 2011 and 2019. He was in office when the state legalized recreational marijuana, although he opposed the move, and has appealed to Colorado's Democratic base.
Analysts and polling show this race as a possible tossup with a definite lean in Hickenlooper's favor.
Alabama: Incumbent Doug Jones (D) vs. Tommy Tuberville (R)
Alabama has the only 2020 Senate race in which Republicans could flip a Democratic seat.
Jones won his seat in a special election in 2017 to fill the seat vacated by Jeff Sessions, who left to become Trump's attorney general. He beat Republican Roy Jones by about 22,000 votes and became the first Democratic senator from Alabama in a quarter-century.
On the GOP side this time is former Auburn University football coach Tommy Tuberville, who's never before run for public office. Tuberville has campaigned in lockstep with Trump in the Magnolia State.
Most experts and poll numbers show Tuberville with a slight edge over Jones.
Maine: Incumbent Susan Collins (R) vs. Sara Gideon (D)
Collins has received criticism from both sides of the aisle during Trump's presidency. Republicans have chided her for opposing Trump on several issues, like the failed GOP healthcare proposal to replace the Affordable Care Act, and she was the only Republican senator to oppose Barrett's nomination.
Democrats have criticized her for taking a more conservative stance on other issues, like voting to acquit Trump during his Senate impeachment trial.
First elected in 1996, Collins follows a tradition of middle-of-the road New England Republicans and has tried to display her independence from the Trump presidency.
Gideon is the speaker of the Maine House and is looking to return the state to its deep Democratic roots in the Senate.
Most experts and polls list this race as a total tossup.
North Carolina: Incumbent Thom Tillis (R) vs. Cal Cunningham (D)
Tillis, elected six years ago, faces a challenge Cunningham, a former state lawmaker.
A member of the Senate judiciary committee, Tillis has taken some criticism for being present at the White House Rose Garden nomination for Barrett, after which may attendees tested positive for COVID-19.Cunningham, also a former Army Reservist, broke fundraising records with almost $80 million in one quarter. But the release of racy text messages and an extramarital affair with a public relations strategist have sullied some of his support.
This race is also listed as a complete tossup by most analysts and pollsters.
Iowa: Incumbent Joni Ernst (R) vs. Theresa Greenfield (D)
Ernst played up her farm roots during her last campaign, saying her experience castrating hogs taught her how to "cut pork."
She was criticized for fumbling a question, though, about the price of soybeans in a recent debate with Greenfield, a real estate executive with no political experience.
Greenfield has attracted of out-of-state money into the race and amassed a war chest totaling twice that of Ernst's.
This race is listed as a tossup by most experts and analytics.
Georgia: Incumbent Kelly Loeffler (R) vs. Raphael Warnock (D)
Georgia is drawing extra attention because both Senate seats are up for election.Loeffler and Warnock are running in a special election to succeed Sen. Johnny Isakson, who said last year he wouldn't run again.
Loeffler, the owner of a woman's basketball team, was appointed to her seat last year by Gov. Brian Kemp. Warnock is a pastor at Ebenezer Baptist Church and a protege of late Sen. John Lewis, who died in July.
Because it's a special election, there are a number of candidates on the ballot, including a Republican challenger, Doug Collins. Loeffler, Warnock and Collins are the front-runners -- with Warnock considered the favorite of the three.
If no candidate wins more than 50% of the vote, a runoff between the two top vote-getters will be held on Jan. 5.
Georgia: Incumbent David Perdue (R) vs. Jon Ossoff (D)
Perdue, a freshman senator, is up against a Democrat who nearly flipped Georgia's House seat in the 6th District during a special election three years ago.
Ossoff won more than 48% of the vote in that contest, but didn't meet the 50% threshold to win the seat outright. He was later defeated in the runoff, but his campaign inspired many Georgia Democrats who will again be voting for him to unseat Perdue.
Ossoff, at 33 one of the youngest Senate candidates in the United States, is a former media executive and investigative journalist.
Perdue, 70, is a close ally of Trump's and a former chemical industry consultant. He has also repeatedly praised Trump's handling of the COVID-19 pandemic.
Most analysts and pollsters see this race as a total tossup.