(NewsNation) — Control of the Senate is up for grabs on Tuesday as more than a dozen critical races could shift the balance of power between Democrats and Republicans.
Democrats have held the slimmest of majorities for the last two years with Vice President Kamala Harris playing tiebreaker on 50-50 votes, but control could be upended.
A total of 34 Senate seats are up for re-election with Democrats and Independents representing 23 of those races.
For Democrats to keep their majority in the Senate, they’d need nearly all incumbents to win reelection and party members to win open seats in Arizona, Michigan and Maryland.
Meanwhile, Republicans only need two seats in total to take the majority.
Polling in the months leading up to the general election has shown Republicans favored to win back control in the Senate, with Democrats defending their seats in some of the tougher-to-hold battleground states, including in Arizona, Florida, Michigan, Pennsylvania and Wisconsin.
Watch as real-time results fill in the tracker below for crucial Senate races:
Arizona
U.S. Rep. Ruben Gallego is facing Trump-backed Republican Kari Lake, who unsuccessfully ran for Arizona governor two years ago.
Florida
Republican U.S. Sen. Rick Scott faces Democratic challenger Debbie Mucarsel-Powell in his bid for reelection.
Maryland
Democratic candidate Angela Alsobrooks and former Republican Gov. Larry Hogan are battling it out for the seat of incumbent Sen. Ben Cardin, who retired after serving 18 years in the U.S. Senate.
Michigan
Democratic Rep. Elissa Slotkin and Republican Mike Rogers are in the running for Democratic Sen. Debbie Stabenow’s seat after the incumbent decided not to run for reelection after holding the seat for nearly 2.5 decades.
Missouri
Republican Sen. Josh Hawley faces Democratic challenger Marine veteran Lucas Kunce in his bid for reelection.
Montana
Three-term incumbent Democratic Sen. Jon Tester is looking to secure another win in his increasingly Republican state of Montana against Republican candidate Tim Sheehy, a decorated former Navy SEAL.
Nevada
Democratic incumbent Sen. Jacky Rosen is in a reelection bid against Republican challenger Sam Brown.
New Mexico
Incumbent Democratic Sen. Martin Heinrich faces off against businesswoman and Republican challenger Nella Domenici in his bid for a third term in the U.S. Senate.
Ohio
Three-term Democratic Sen. Sherrod Brown is defending his seat in Republican-leaning Ohio against GOP businessman Bernie Moreno.
Pennsylvania
Democrat incumbent Sen. Bob Casey Jr. faces a challenge from Republican rival David McCormick.
Texas
Two-term Sen. Ted Cruz is defending his seat in Republican-leaning Texas against Democratic challenger and former NFL linebacker Colin Allred.
West Virginia
Republican West Virginia Gov. Jim Justice faces Wheeling’s Democratic Mayor Glenn Elliott in a race to fill the seat left open by independent Sen. Joe Manchin, who held the seat for 14 years.
Wisconsin
Democratic Sen. Tammy Baldwin is defending her seat against Republican challenger Eric Hovde, a wealthy real estate executive.
NewsNation’s Ashley Soriano and Jeff Arnold contributed to this story.