These Senate, House races will determine Congress’ balance of power: A visual breakdown

With Congress as narrowly divided as it has been in two decades, voters in a few closely contested races in the Senate and House of Representatives still could tip the balance of power in both houses over to Republicans. 

It hasn’t been since George W. Bush’s final term, the 110th Congress, that both flipped from Republican to Democratic control, but Republicans’ prospects for taking control of the Senate have narrowed. 

With many Americans taking advantage of early voting in these midterm elections, we could be many hours or days away from knowing the makeup of the 118th Congress. Also, the close Senate race in Georgia won’t be decided until a December runoff. 

As of Wednesday afternoon, just four Senate seats and five dozen House seats were left to determine the balance of power in the 118th Congress. 

Several Senate races were considered tightly contested as voters went to the polls Tuesday, but only one has resulted in a net change in the Senate: John Fetterman’s victory over Dr. Mehmet Oz in Pennsylvania means Fetterman will fill the seat vacated by Republican Pat Toomey. 

Democrats now hold a 220-212 majority in the House of Representatives, with three vacancies.

The Cook Political Report estimated more than 60 of the races were competitive or toss-ups. Nearly as many are still undecided. Of the eight toss-ups that USA TODAY profiled, five have been decided: four by a Democratic candidate and one by a Republican.   

Thirty-five Senate seats were up for election in 34 states this year. With four seats still to be determined, Fetterman’s victory in Pennsylvania is the only new seat for either party. 

The Senate has been evenly split throughout the 117th Congress, putting tiebreaking, simple-majority votes in the hands of Vice President Kamala Harris. If Republicans gain just one seat, they will retake the control they relinquished in the 2020 election.  

Members of the House of Representatives serve two-year terms, so all 435 seats were up for election. That said, the Cook Political Report estimated 85% of the seats were at least likely to be unchanged: 199 Republican and 172 Democratic. That’s where the tally largely stood for most of Wednesday morning. 

Before Tuesday’s vote, analysts and candidates said they expected Democrats would lose seats. Just six new seats would allow Republicans to regain control. 

“Democrats are going to lose seats,” said Chris Warshaw, a professor at George Washington University in Washington, D.C. The question, Warshaw said, was how much Democrats could mitigate their losses.  

Control of Congress swung between the parties in the 1950s, but in the 83rd Congress – two years before John F. Kennedy’s election in 1960 – Democrats claimed major wins in both the House and Senate.

Democrats held large majorities for years until 1980, when Ronald Reagan’s election and presidency helped push American politics rightward and Republicans regained control of the Senate for three terms. 

Since the 1950s, control of both the House and Senate by one party has shifted only twice to the other. A look at how control has shifted in Congress since Jimmy Carter was elected president and the 95th Congress was seated.

In a tweet on the eve of the election, Elon Musk encouraged Americans on his new social media platform to vote Republicans into Congress and counterbalance a Democratic president: “Shared power curbs the worst excesses of both parties.”

Americans surveyed in an October USA TODAY/Suffolk Poll appear to agree with Musk to a degree.

Almost half (49%) said they’d like Congress to stand up to President Joe Biden, but the exact same percentage said they expect a change in Congress would mean little change in legislation in the next two years.