Key Senate Races to Watch

The battle for control of the U.S. Senate in the 2024 election is considered by many political observers to be just as significant as the race for president. Whichever political party wins control of the Senate will impact the amount of influence the next president has. Democrats currently hold a narrow 51-to-49 seat edge in the Senate, counting the four independents who caucus, or ally, with the Democratic Party.  

Thirty-four of the Senate’s 100 seats are up for election on November 5th. To maintain control, Democrats would have to win all their incumbent seats plus one open seat and also win the presidential election. That would allow the Democratic vice president to break any tie votes.  

Republicans need to win two Democratic seats to take control of the Senate–or win one Democrat’s seat and win the White House to give them a Senate majority with a vice-presidential tiebreaker vote. The retirement of Senator Joe Manchin in West Virginia increases the chances that a Republican will win his seat because the state leans Republican in many other political offices. Manchin switched his party affiliation from Democrat to Independent in 2024. He has been one of the four independents to ally with the Democrats.  

Many of the Senate races are close as October begins. Here are five key races to watch. 

Ohio

Democratic Senator Sherrod Brown is seeking his fourth term. In 2006 Brown flipped the seat from Republican to Democrat. During his many years in the Senate, Brown established himself as a supporter of working-class people. While being the incumbent provides advantages in an election, Ohio is becoming an increasingly Republican state. Trump won Ohio in 2020 by eight points. The Ohio GOP controls both chambers of the state legislature and the governor’s office. This favors Brown’s opponent, Republican Bernie Moreno. He is a businessperson whom former president Donald Trump has endorsed. Moreno was born in Colombia and moved to the United States when he was 5 years old. He became a citizen at age 18. Political experts call this Senate race a “toss-up.” 

Montana

The Trump-backed challenger in Montana is Republican businessperson Tim Sheehy, a former Navy SEAL. He is hoping to unseat incumbent Democratic Senator Jon Tester. Tester, a former schoolteacher and farmer, is seeking a fourth term. Tester has won his previous races by an average margin of fewer than three points. This race, however, is considered much tougher. Trump won Montana by 16 points in 2020. For Tester to win, he will need Republican voters to split the votes on their ballot—voting for him and for Trump rather than voting along party lines. The race is also being called a “toss up.”  

Michigan

The retirement of Democratic Senator Debbie Stabenow has opened her seat to a contest between Republican Mike Rogers and Democratic U.S. Representative Elissa Slotkin. Rogers is a former FBI agent and member of the House of Representatives from 2001 to 2015. Slotkin is a former national security official who began serving in Congress in 2023. She has raised more than four times as much money as Rogers for this contest. While a Republican has not won a Senate race in Michigan since 1994, political experts are calling this race a “toss-up.” 

Arizona

Democratic U.S. Representative Ruben Gallego and Republican Kari Lake are competing for the seat that becomes available with the retirement of Independent Senator Kyrsten Sinema. Like West Virgina Senator Joe Manchin, Sinema voted alongside Senate Democrats. Lake is a former television news anchor who became well-known nationally during her involvement in former president Trump’s MAGA (Make America Great Again) movement. She unsuccessfully ran for Arizona governor in 2022. Gallego served in the U.S. Marine Corps in Iraq and as a state representative in Arizona. He currently represents Arizona’s seventh district in the U.S. House of Representatives where he has served since 2015. Experts say this race “leans Democratic.” 

Pennsylvania

Recent polls show that incumbent Democratic Senator Bob Casey, Jr., holds a small lead over challenger Republican Dave McCormick. Casey has represented Pennsylvania in the U.S. Senate since 2007. This makes him the longest-serving Democratic U.S. senator in Pennsylvania history. He is now seeking his fourth term. Casey was born and raised in Scranton, the same hometown as President Joe Biden. McCormick served as CEO of Bridgewater Associates, one of the world’s largest private investment firms from 2020 to 2022. He also served in the George W. Bush administration as the Under Secretary of the Treasury for International Affairs. Experts say this race “leans Democratic.” 
 

Other Races to Watch 

Other Senate races to watch are in Maryland, Nevada, and Wisconsin. Democrats are also spending millions of dollars in television advertising in Florida and Texas, hoping to defeat the Republican incumbents.  

Dig Deeper Research the ways in which political control of the U.S. Senate can impact government. How does it affect the president’s influence? How can the control of a single party in the Congress and Presidency influence legislation?