On July 25, Troy Jackson (D) won the nominating convention to replace Graham Platner (D) as the Democratic nominee for the U.S. Senate general election in Maine. This is the first time since 1918 that a U.S. Senate nominee has been replaced in Maine.

After a woman accused Platner of sexually assaulting her in 2021, the Maine Democratic Party held a meeting on July 8 of more than 100 state committee members. During the meeting, state committee members voted to hold a nominating convention if Platner withdrew from the general election. After the vote, Platner announced that he would withdraw from the general election and officially withdrew on July 10.

On July 25, 601 delegates voted on a replacement candidate during the nominating convention. Before that convention, delegate nominating conventions were held in all 16 of the state’s counties to select 500 of those delegates. The number of delegates from each county was based on voter turnout in the 2024 Democratic primary. The remaining 101 delegates were state committee members. 

Only individuals who were registered Democrats as of June 9 were able to vote in the delegate nominating conventions and participate as convention delegates. 

During the nominating convention, Jackson defeated Saundra Pelletier (D) 566 votes to five votes. Jackson will now face incumbent Sen. Susan Collins (R), who first took office in 1997, in the general election. 

As of July 21, The Cook Political Report, DDHQ/The Hill, and Sabato's Crystal Ball rated the general election as a toss-up. Inside Elections rated it tilt Republican.

Jackson is the 28th replacement nominee for a U.S. Senate candidate since 1918 and the 15th Democratic replacement candidate. 2026 is tied with 1936 and 2002 for the second-most Senate nominee withdrawals (voluntary, misconduct-related, or due to death), with three withdrawals each. The year with the most withdrawals was 2014, with five. 

In addition to Platner, there have been two other nominee withdrawals in U.S. Senate elections this year: Cindy Burbank (D), who withdrew from the Nebraska general election on July 17, and then-incumbent Sen. Lindsey Graham (R-S.C.), who died on July 11. There will be a special Republican primary on Aug. 11 to select a new Republican nominee in South Carolina. However, it is unlikely that there will be one in Nebraska after the state's Democratic Party endorsed the nonpartisan candidate, Dan Osborn, in August 2025.

Additionally, the Democratic nominee for the U.S. Senate in Idaho, David Roth (D), said on July 28, "In the coming weeks, I will work with my team to meet our remaining financial obligations and complete the formal withdrawal process."

Since 1918, only seven U.S. Senate replacement nominees — three Democrats, three Republicans, and one Farm-Labor Party member — have been elected. The most recent was Frank Lautenberg (D-N.J.), who was elected in 2002.