Massachusetts Democrats will vote Tuesday in a Senate primary pitting 80-year-old Sen. Ed Markey against Rep. Seth Moulton, who has built much of his campaign around the argument that Democrats need younger leaders.

Markey is seeking a third full Senate term, while Moulton is trying to unseat a fellow Democrat who has served in Congress for nearly five decades.

Moulton makes the case for younger leadership

Moulton has repeatedly called for “generational change,” arguing that Democrats need younger leaders and calling for age limits for members of Congress.

Markey has defended his record and has some of the party’s most prominent progressives behind him, including Sens. Bernie Sanders, Elizabeth Warren and Alexandria Ocasio-Cortez.

Markey has been in Congress for nearly 50 years — serving almost 37 years in the House before winning his Senate seat in 2013. His congressional career began more than five years before Moulton was born.

Moulton argues that longevity strengthen his case for a change.

Markey has also drawn support from younger Democrats, including the High School Democrats of America and College Democrats of America.

Markey holds a wide polling lead

An Emerson College poll conducted Aug. 28-29 found 60.4% supporting Markey and 32.8% backing Moulton among likely Democratic primary voters and those who had already voted. Another 6.7% were undecided.

Moulton does have the backing of the The Boston Globe editorial board, which endorsed him last month and argued that he could bring “new vision and vigor to an aging, ailing, and deeply unpopular Democratic party.”

The board acknowledged that Markey “still looks and sounds sharp” and brings valuable experience, but ultimately sided with Moulton’s argument for new leadership.

Markey faced another younger Democratic challenger in 2020, defeating then-Rep. Joseph Kennedy III by 10 points in the Democratic primary.

Polls close at 8 p.m. ET Tuesday.

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