Sen. Ed Markey defeated Rep. Seth Moulton in Massachusetts’ Democratic U.S. Senate primary on Tuesday, September 1, 2026, giving the 80-year-old incumbent a decisive victory over a challenger who made generational change the defining issue of the race.
Markey now advances to the November 3 general election against Republican John Deaton. The result was projected shortly after Massachusetts polls closed at 8 p.m. ET and represents one of the clearest tests yet of whether Democratic voters are ready to replace longtime incumbents primarily because of age.
Sen. Ed Markey will win the Democratic nomination for US Senate in Massachusetts, CNN's Decision Desk projects, fending off a primary challenge from Rep. Seth Moulton as he seeks a third full term. https://t.co/nsOnjPnqab pic.twitter.com/FC8H9WqyHX
— CNN (@CNN) September 2, 2026
Ed Markey defeats Seth Moulton
Moulton, 47, argued throughout the campaign that Massachusetts needed younger political leadership. The six-term congressman positioned himself as an alternative to a senator whose congressional career began in 1976.
Markey countered that voters should focus on ideas and policy rather than age. He emphasized his progressive record on climate, health care and other Democratic priorities and entered Election Day with support from prominent figures including Massachusetts Sen. Elizabeth Warren, Sen. Bernie Sanders and Rep. Alexandria Ocasio-Cortez.
Public polling had pointed toward a Markey victory. An August UMass poll put him at 60% among Democratic voters who supported or leaned toward a candidate, compared with 32% for Moulton. A later University of New Hampshire poll showed Markey leading 63% to 28%.
Moulton responds after losing primary
Moulton conceded Tuesday night and congratulated Markey, but said his campaign’s argument about political renewal would continue.
He told supporters that challenging established political leadership remained necessary and expressed hope that other candidates would be encouraged to run rather than simply wait for long-serving officeholders to leave.
The defeat leaves Moulton without his House seat after he gave up Massachusetts’ 6th Congressional District to pursue the Senate nomination.
Markey has beaten a younger challenger before
This was not Markey’s first primary shaped by generational politics. In 2020, Rep. Joe Kennedy III challenged him for the Democratic Senate nomination. Markey won that contest 55% to 45%.
Six years later, Massachusetts Democrats have again chosen Markey over a considerably younger member of Congress, making his victory particularly significant during a 2026 primary season in which several veteran lawmakers around the country have faced younger challengers.
Other Massachusetts primary results
House Minority Whip Katherine Clark defeated Tarik Samman and Jonathan Paz in the Democratic primary for Massachusetts’ 5th Congressional District.
Rep. Jake Auchincloss defeated AI researcher Jason Poulos in the 4th District Democratic primary, while Rep. Bill Keating defeated Craig Swallow in the 9th District.
In the governor’s race, businessman Michael Minogue defeated former MBTA administrator Brian Shortsleeve for the Republican nomination. Minogue will challenge Democratic Gov. Maura Healey, who was unopposed in her primary.
Other closely watched contests included Rep. Stephen Lynch against Patrick Roath in the 8th District, Rep. Richard Neal against Jeromie Whalen in the 1st District and the crowded Democratic contest to replace Moulton in the 6th District.
Political turnover has become a wider theme in recent elections. Similar questions about established leadership and changing voter preferences have surfaced in races such as the Secret Harbour by-election results and the London by-election triggered after Keir Starmer quit as an MP.
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More than 555,000 votes cast early
Massachusetts entered Election Day with 555,525 ballots already cast, according to figures from the Secretary of the Commonwealth’s office cited in election reporting. That included 483,946 mail ballots and 71,579 in-person early votes.
Turnout has varied considerably in recent Massachusetts primaries. It was 16.7% in 2024, compared with 36.58% in 2020 when Markey faced Kennedy.
DOJ monitors Massachusetts polling places
The Justice Department’s Civil Rights Division deployed 12 election monitors to polling locations in Boston, Lowell and New Bedford. Federal monitoring does not itself indicate wrongdoing or problems with the election results.
Who does Ed Markey face next?
Markey will face Republican John Deaton in November. Deaton was unopposed for the Republican Senate nomination, setting up another statewide contest between the two candidates.
Massachusetts has strongly favored Democratic candidates in recent federal elections, giving Markey an advantage heading into the general election, although the seat will ultimately be decided by voters.
The Massachusetts Elections Division provides official information on voting, ballot tracking and certified election results.
For Markey, Tuesday’s result answered the primary campaign’s central question: Democratic voters were offered a direct choice between experience and generational change, and they chose to keep the longtime senator as their nominee.
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