The question of which party will take control of the Senate was left unresolved early Wednesday morning due to a lack of final results in a number of key races.But Democrats' path to flipping Republicans' 53-seat Senate majority narrowed significantly Tuesday night as key Republicans held off promising, well-funded challengers and managed to flip a seat in Alabama thanks to a win by former Auburn football coach Tommy Tuberville.Tuberville defeated incumbent senator Doug Jones, who was considered uniquely vulnerable since his election was aided by sexual assault allegations leveled against Roy Moore in the 2017 special election.In Montana, Republican senator Steve Daines was projected to defeat Steve Bullock, the outgoing governor. The GOP also took three open, albeit relatively safe, seats in Kansas, Tennessee and Wyoming.However, in Colorado, Democrats flipped incumbent Republican senator Cory Gardner's seat, with John Hickenlooper declaring victory. In Arizona, Democrat Mark Kelly defeated GOP senator Martha McSally, for a net gain so far of one seat.Since polls closed on Tuesday, the Associated Press has called 29 of 35 Senate races: twelve in favor of Democrats and 17 in favor of Republicans.Two high-profile contests featuring Republican incumbents — Senator Thom Tillis's race against Army veteran Cal Cunningham and Susan Collins' face-off with Maine state House speaker Sara Gideon — were too close to call Wednesday morning, although both incumbents were leading.John James was also leading incumbent Democrat Gary Peters in Michigan but the race was too close to call as of Wednesday morning.Senator Lindsey Graham (R., S.C.) was able to fight off Democratic challenger Jaime Harrison, who smashed Senate fundraising records by hauling in $57 million during the third quarter — twice as much as Graham had raised in the previous six quarters combined. Though Graham won, Harrison had proven a formidable opponent to the South Carolina senator who serves as the chairman of the Senate Judiciary Committee. Graham had been scorned by Democratic donors for leading the push to confirm Judge Amy Coney Barrett to the Supreme Court ahead of Election Day. In Kentucky, Senate majority leader Mitch McConnell (R.) won reelection, holding off Democratic challenger Amy McGrath, a retired Marine combat pilot, to win a seventh term in the Senate.Shelley Moore Capito became the first Republican in West Virginia to be reelected to the Senate in more than a century on Tuesday night, according to the AP. Senators Joni Ernst (R., Iowa), John Cornyn (R., Texas), Ben Sasse (R., Neb.), Tom Cotton (R., Ark.), Cory Booker (D., N.J.), Dick Durbin (D., Ill.), and Ed Markey (D., Mass.) all won reelection as well.Georgia’s special Senate election is headed for a runoff between Democrat Raphael Warnock and incumbent senator Kelly Loeffler as no candidate in the crowded race was able to pass 50 percent of the vote needed to win, according to the AP. There is a possibility Georgia's other Senate seat will face a runoff election as well.Runoffs in Georgia could leave the fate of the Senate unknown for weeks after November 3.In the House, the AP has called 189 races in favor of Democrats and 181 in favor of Republicans, dashing Democratic hopes for a sweeping blue wave. Newcomer Republicans Madison Cawthorn in North Carolina, a 25-year-old paraplegic survivor of a near-fatal car crash, and Marjorie Greene, who has openly supported the conspiracy theory QAnon, in Georgia, were among the high-profile victors.Cawthorn, who became the youngest ever person elected to the House, taunted his opponents after the race was called, tweeting "cry more, lib."In Florida's 27th Congressional District, Republican Maria Elvira Salazar has ousted incumbent Representative Donna Shalala, a Democrat, the AP reports.In the Senate, 23 Republican-controlled seats and 12 Democrat-controlled seats are up for election: seven of the posts, all of which are currently Republican-held, have been rated a “toss-up” by the Cook Political Report, a nonpartisan outlet dedicated to analyzing and predicting elections.Democrats would need a net gain of three seats to control the Senate in the event that Joe Biden wins, as the vice president can act as a tie-breaker on Senate votes. Should Trump and Vice President Mike Pence win, Democrats would need a net gain of four seats to wrest control from the current Republican majority. There are two independent senators who caucus with Democrats.Tillis's race against Cunningham in North Carolina has also attracted a great deal of national attention. In early October it was revealed that Cunningham, who had run on a campaign of "truth" and "honor," had allegedly had an extramarital relationship. The U.S. Army Reserve is investigating Cunningham, who is a Reserve officer, over reports that he had an affair this year with Arlene Guzman Todd, whose husband has served in the Army.However, the affair allegations don't seem to have impacted Cunningham much: a Friday poll from Marist College found the Democrat up by 10 points, 53 percent to 43 percent. A New York Times poll showed him up by three points, 46 percent to 43 percent.In Maine, Susan Collins is in danger of losing the seat she has held since 1997 to challenger Sara Gideon after mounting criticism for her decision to support the confirmation of Supreme Court Justice Brett Kavanaugh and to vote to acquit President Trump in his Senate impeachment trial earlier this year. Gideon, who serves as state House speaker, leads in the polls. However, Michigan's Democrat-held seat may be in danger of flipping, as incumbent Senator Gary Peters holds a single-digit lead over Republican Army veteran John James. The incumbent's slight lead has largely remained within the margin of error in recent polls. RealClearPolitics rates the race a "toss-up."In the House, Democrats will look to maintain or grow their majority, which currently stands at 232 seats to Republicans’ 198. The Cook Political Report lists 25 House seat races as “toss-up,” 16 of which are Republican seats in danger of flipping.Assuming there are no vacancies and no members from a third party, Democrats or Republicans need a minimum of 218 seats to ensure control of the House of Representatives. As Democrats currently hold 232 seats, they would need a net loss no greater than 15 seats to remain in control. Republicans have 198 seats.