U.S. Senator Susan Collins (R-ME) walks at the Senate Subway heading to a vote on the ninth day of a partial shutdown of the federal government at the U.S. Capitol in Washington, D.C., U.S. October 9, 2025. REUTERS/Kent Nishimura/File Photo

By Bo Erickson

WASHINGTON (Reuters) -Democrats face an uphill battle to recapture a U.S. Senate majority in the November 2026 midterm elections, as Republicans are defending just two seats seen as competitive by nonpartisan analysts and hold a 53-47 majority.

Democrats are defending four competitive seats and would need to pick up another four to take the majority. Elections will be held for 33 of the chamber's 100 seats next year.

Below are the key Senate races to watch:

MAINE

Five-term Republican Senator Susan Collins of Maine is no stranger to a competitive election. As chair of the Senate Appropriations Committee, she oversees government spending levels, a job that has also led to clashes with the Trump administration this year.

A party moderate, she is deemed the Republicans' best chance at holding the seat. Her challenger is likely to be either the state's current Democratic governor, Janet Mills, or the progressive rival, Graham Platner, who will face off in a June 9 primary.

Mills, 77, is older than Collins, 72, and would be the oldest senator ever elected to a first term. The Democratic base cheered Mills when she stood up to President Donald Trump in defense of transgender rights. Platner is an oysterman and Marine Corps veteran, whose popularity as a political outsider has risen by calling out the establishment.

NORTH CAROLINA

Republicans will look to defend an open seat in North Carolina, since Senator Thom Tillis opted to retire after clashing with Trump over the president's tax and spending law. The state's former Democratic governor, Roy Cooper, has launched a run, aiming to bring his southern, moderate style to Washington.

Trump won the state in 2024 against Vice President Kamala Harris and is expected to be involved in the race as the Republican candidate, Michael Whatley, previously led the party's political arm as chairman of the Republican National Committee.

GEORGIA

In the four competitive Senate races that Democrats need to defend, two are in states with Republican governors, underscoring the political challenge. Democratic Senator Jon Ossoff is running for reelection in Georgia after flipping the seat in 2020.

Ossoff, 38, is the youngest current senator. He has mostly kept his head down in his first term, primarily speaking in defense of his state, such as when the administration started reworking the Atlanta-based Centers for Disease Control and Prevention.

Trump has not endorsed anyone ahead of the May 19 Republican primary, extending the three-way competition between two U.S. representatives, Mike Collins and Buddy Carter, and the Republican governor's pick Derek Dooley, an attorney and former college football coach.

NEW HAMPSHIRE

In the Northeast is another state with a Republican governor that Senate Democrats need to defend, after the retirement of three-term Senator Jeanne Shaheen. The New Hampshire race's three main contenders are familiar to the state's electorate, famous for civic engagement.

U.S. Representative Chris Pappas, a four-term centrist Democrat, would be the first openly gay man elected to the Senate.

In an unusual twist for the September 8 Republican primary, both challengers have already served in the Senate. Former Senator John E. Sununu represented the state for one term until he lost in 2008, and more recently, former Senator Scott Brown served in the Senate until 2013, representing neighboring Massachusetts.

MICHIGAN

Another battleground state that most recently picked Trump in the close 2024 election, Michigan's Senate race is open after the retirement of Senator Gary Peters, a Democrat.

Multiple Democrats, spanning the party's ideological bounds, plan to contest the August 4 primary. Four-term U.S. Representative Haley Stevens is courting her party's leadership, as Michigan state Senator Mallory McMorrow and Abdul El-Sayed, a progressive activist, try to show they can break the establishment mold.

Trump endorsed former longtime U.S. Representative Mike Rogers for his second Senate campaign. The Republican served in the Army, worked in the FBI, and ran unsuccessfully for the Senate in 2024.

MINNESOTA

The election to replace retiring Senator Tina Smith, a Minnesota Democrat, is focused within her own party. U.S. Representative Angie Craig, the top agriculture Democrat leading the charge on criticizing the impact of Trump's tariffs on the heartland, is making an electability argument in the contest against the more progressive Lieutenant Governor Peggy Flanagan, who would be the first Native American female senator, and is also contesting the August 11 primary.

Republicans have only one main candidate: former NBA player Royce White, a second-time candidate who lost in the 2024 Senate election by more than 15 points.

(Reporting by Bo Erickson; editing by Scott Malone and Rod Nickel)