Not only is there a clash of ages, but also one of political ideologies, as this race for senator is another example of Democrats choosing between having progressives lead the party and maintaining the status quo with moderates at the helm.

In an interesting role reversal, Markey, who has been an established figure within the party for over 30 years, has positioned himself as the voice of the progressive left, while Moulton has moved some of his more moderate positions closer to those of his older rival in an effort to win over younger voters.

The incumbent senator has earned his fair share of high-profile endorsements from fellow progressive Democrats, including Sens. Elizabeth Warren and Bernie Sanders, as well as Rep. Alexandria Ocasio-Cortez.

Moulton was endorsed by The Boston Globe. He also has the support of several of his current and former Democratic House colleagues, including New Jersey Gov. Mikie Sherrill.

Markey, who turned 80 in July, is the second-oldest sitting U.S. senator seeking reelection in 2026. He took the seat in 2013 after serving nearly 37 years in the House. The oldest U.S. senator seeking re-election is Iowa Sen. Chuck Grassley, who has served in the Senate since 1981.

Moulton has centered his campaign on Markey's age and the need for generational change in leadership, arguing that Markey’s time as a senator has not been nearly productive enough to confront the Trump administration and advance priorities such as the Green New Deal, the latter of which has been a focal point in the incumbent's campaign.

"I served with some of the most amazing leaders in my life in the Marines, but at 23 years old, they don't get to run for Congress," Moulton said at last week's final debate. "I think we should have upper age limits as well."

During the recent debate, Markey attempted to dispel any doubts regarding his age, saying, “I think everyone watching this debate can see that I’m more energized than I’ve ever been before in my life. I am crisscrossing the state. I’m fighting for families.”

He then tried to flip the notion that Moulton was winded from this campaign, saying, “Congressman Moulton has a hard time keeping up with me in the course of this campaign.”

Moulton, a Marine Veteran and Harvard graduate, has served as U.S. Representative for Massachusetts’s 6th District since 2015. According to his campaign website, Moulton led the creation of the 988 Suicide and Crisis Lifeline, which has connected Americans with mental health services, and has authored legislation to expand disability coverage for families affected by ALS.

Markey’s platform includes providing affordable healthcare, expanding educational opportunities, tackling climate change, and establishing more rights for immigrants and LGBTQ+ Americans.

Age is a Factor

Calls for concern over Markey’s age are valid, as the incumbent senator would be 86 at the end of his third term if he were to secure the nomination.

An ongoing discussion about Kentucky Sen. Mitch McConnell’s health has raised doubts about the 84-year-old’s ability to maintain his position. Having been hospitalized for around three months, the public grew skeptical that McConnell had passed away while in hospital care.

In early August, McConnell’s office announced that he had been discharged from the hospital and was receiving rehabilitation care; however, he had not made a public appearance to lend credence to his supposed improved health.

Kentucky Gov. Andy Beshear has made public statements saying that McConnell’s office has not responded to his requests for more information about the senator’s health and ability to serve following his hospitalization.

Hoping to convince naysayers who want younger representation in Congress, Markey sought to cast his age as experience. “I’ve been standing up to the bosses for a long time, so I know no one gives it to you,” he says in one of his most prominent ads, featuring Warren and Sanders. “We have to fight for it.”

Markey notably fended off a 2020 challenge from Rep. Joe Kennedy III, a younger rival from one of the nation’s most famous political families. Kennedy, then 39, was defeated by Markey after the incumbent senator rallied support from young progressives, convinced he would be the most effective candidate to take on the party’s establishment.

A final Emerson College Polling survey released Sunday found Markey leading Moulton 60% to 33% among likely Democratic primary voters, with 7% undecided. The poll marked a significant improvement for the incumbent since May, when he led by just five points.

Executive director of the Emerson College Polling made a comment regarding Markey's lead over Moulton, saying, “If these numbers hold, this race will mirror Markey’s successful ‘peak-late’ approach to winning in 2020, when the Senator moved from 16 points behind in our May poll to 12 points ahead in August, a 28-point swing, ultimately winning by 11. This cycle, the margin similarly shifted from a five-point lead in May to a 30-point lead in the final Emerson poll.”