What’s happening: Massachusetts Sen. Ed Markey fended off a primary challenge from Rep. Joe Kennedy III in a tightly watched race Tuesday seen by many as a referendum on the state of the Democratic Party.

Markey, who has served in Congress for more than 40 years, bucked a trend that has seen older, established Democrats lose primary races to younger challengers. He won by aligning himself with the left wing of the party and earning the endorsement of progressive stars like Rep. Alexandria Ocasio-Cortez, who herself had unseated a long-serving Democratic representative in 2018.

Kennedy, the 39-year-old grandson of former Sen. and U.S. Attorney General Robert F. Kennedy, led by a significant margin in polls when he entered the race just over a year ago. But that lead gradually evaporated during the course of a heated campaign in which Markey, 74, built a devoted online following among younger progressives who bolstered his candidacy through memes while leveling harsh criticism at Kennedy. In the end, Markey won the race by more than 10 points.