Democrats are resisting a Republican offensive aimed at destroying their narrow majority in the Senate.
Analysts say regaining control of the upper house of Congress could be the Republican Party’s best chance of success in the November election, surpassing its chances of retaking the White House or even retaining control of the House of Representatives.
But thanks to the enthusiasm of Kamala Harris’ campaign, Democrats are still competitive.
What is the current composition of the Senate?
Democrats currently hold 48 of the 100 seats in the 100-member chamber, plus the support of three independent senators who are on the party’s caucus and support it on key votes. Republicans hold 49 seats, meaning they need to win only two in November — when a third of the seats are up for grabs — to regain control.
What are the chances of the Republicans taking power?
On the face of it, the GOP has the upper hand. The retirement of Joe Manchin, a centrist Democrat from West Virginia with a track record of taking Republican positions, will almost certainly result in a GOP gain in a state that has become a party stronghold.
If Donald Trump were to retake the White House, a victory in West Virginia alone would be enough to flip the Senate to the Republicans, with the vice president having the deciding vote in a 50-50 split under the US Constitution.
Related: Republicans hope for Senate majority after strong West Virginia primary result
Where are incumbent Democrats most vulnerable?
Two incumbent Democratic senators in GOP heartland states are seen as particularly vulnerable: Jon Tester of Montana and Sherrod Brown of Ohio. The latter is a former battleground that Trump won in recent elections and is now seen as solid Republican territory.
In states that have become increasingly conservative, Tester and Brown have both tried to remain competitive by emphasizing their independence from the more liberal national party establishment. Both sat out last month’s Democratic national convention in Chicago to focus on luring independents and swing voters whose support is seen as vital to holding on to their seats. The Cook Political Report has labeled both contests as toss-ups.
Montana: John Tester vs. Tim Sheehy
Tester, who has held the seat since 2006, is running for a fourth term in a state that Trump won by 16 points four years ago over Tim Sheehy, a former Navy Seal and businessman who has the former president’s backing.
Ohio: Sherrod Brown vs. Bernie Moreno
Brown has been in the Senate as long as Tester and is also seeking a fourth term. His opponent, Bernie Moreno, is another Trump-backed candidate who was not the choice of Ohio’s Republican elite.
Key states where Republicans hope to make gains in the presidential election
Nevada: Jacky Rosen vs. Sam Brown
Jacky Rosen, a senator first elected in 2018, faces a challenge from Sam Brown, a Republican with a strong past but a thin political resume. A graduate of West Point Military Academy and veteran of the long U.S.-led effort in Afghanistan, Brown narrowly survived a roadside bombing in Kandahar that left him permanently scarred. Like Tester and Brown, Rosen opted to skip the recent Democratic convention to focus on her Senate defense.
The Cook Report categorizes the race as Democratic.
Related: The Wisconsin race that could flip the Democratic majority in the US Senate
Wisconsin: Tammy Baldwin vs. Eric Hovde
Two-term Sen. Tammy Baldwin is running against Eric Hovde, a wealthy GOP banker and businessman who is financing his own campaign. But his local credibility has been questioned by Democrats who have highlighted his Southern California connections.
The race is also rated as Democratic-leaning by the Cook Report.
Pennsylvania: Bob Casey v David McCormick
Incumbent Democratic Senator Bob Casey is running against David McCormick, former chief executive of Bridgewater Associates, one of the world’s largest hedge funds.
Casey is favored to retain his seat, in part because of his strong local name recognition. His opponent has already suffered a defeat in a race for Senate in Pennsylvania, having narrowly lost the state’s 2022 Republican primary to Mehmet Oz, who then lost to Democrat John Fetterman in the runoff election for a seat left vacant by the resignation of a GOP incumbent, Pat Toomey, one of just seven Senate Republicans who voted to convict Trump of the Jan. 6 attack on the U.S. Capitol during his second impeachment trial.
The Cook Report considers the party to be Democratically oriented.
Arizona: Ruben Gallego against Kari Lake
A seat left vacant by the retirement of Kyrsten Sinema, a former Democrat who left the party to become an independent, is now a prime target of Kari Lake, a former TV news anchor who has positioned herself as an outspoken Trump supporter and arch-enemy of the lie that the 2020 election was stolen. She repeated the tactic when she lost the 2022 Arizona gubernatorial race to Democrat Katie Hobbs. Her opponent is Gallego, a Democrat in the House of Representatives and a former Marine veteran who served in Iraq.
According to the Cook Report, the election has a Democratic slant.
Michigan: Elissa Slotkin vs. Mike Rogers
Here, Republicans are on the offensive to replace a retiring Democratic senator, Debbie Stabenow, who is stepping down after 24 years. Elissa Slotkin, currently a Democratic member of the House of Representatives, will try to fill her shoes. She will be running against Mike Rogers, a mainstream Republican who once said his party had to look beyond Trump before it could change course and embrace him, earning him the former president’s endorsement.
According to the Cook Report, the race is a toss-up.
Maryland: Angela Ookbrooks v Larry Hogan
Solidly Democratic Maryland, which includes the liberal suburbs of Washington, DC, is critical to the party’s hopes of retaining its majority in the Senate.
Instead, it’s turning into a dogfight between Democratic candidate Angela Alsobrooks, the governor of one of Maryland’s largest counties, and the state’s former governor, Larry Hogan. A recent poll by the American Association of Retired Persons showed the two both polling at 46 percent — this despite Kamala Harris holding a nearly 20 percent lead in the presidential race. Part of the explanation is the moderate public profile of Hogan, a traditional Republican who has positioned himself as an anti-Trump Republican and has said he won’t seek the former president’s endorsement.
Buoyed by the recent poll, Hogan has now gone even further. In a new ad, he positions himself as one of the few Republicans who never “caved” to Trump and praises his decision to send in the Maryland National Guard to suppress the January 6, 2021, attack on the US Capitol.
The state, which Trump lost to Joe Biden by 33 points in 2020, is in a precarious position, according to the Cook Report.
Related: Violence and instability have become a hallmark of American political life, not a flaw.
Are there any outsiders left?
Florida: Where incumbent Republican Rick Scott is being challenged by Democrat Debbie Mucarsel-Powell.
Texas: Colin Allred, another Democrat, is trying to unseat embattled Senator Ted Cruz, who ran unsuccessfully for the Republican presidential nomination in 2016.
The Cook Report estimates that both races are likely to be Republican.
Read more about the 2024 US elections:
