Joe Kennedy defeated

Congressman Joe Kennedy, long seen as a rising star, crashed to defeat on Wednesday in his bid for a US Senate seat, the first time the storied American political dynasty lost a state election in Massachusetts.

Incumbent Senator Ed Markey, a political veteran who re-cast himself as the fiery liberal in the race, harnessed the state’s progressive energy to handily turn back a primary challenge from Joseph Kennedy III, the grandnephew of assassinated president John F. Kennedy.

The 39-year-old Kennedy said he called Markey "to congratulate him and to pledge my support in the months ahead." With votes still being counted, Markey was leading around 55 percent to 44 percent.

The race pitted two well-liked progressives against each another, but it was Markey’s organizational energy and appeal to the ascendant left that won out over Kennedy. "Tonight is more than just a celebration of an election, it is a celebration of a movement," Markey wrote on Twitter.

Representative Alexandria Ocasio-Cortez, a figurehead of the party’s progressive wing, congratulated Markey on the win. "Yours is a victory for the progressive movement, for 21st century policy, and for the Green New Deal," she wrote on Twitter.

The Green New Deal, an economic plan to tackle climate change, was co-authored by Markey and Ocasio-Cortez. Since he is not allowed to be on the ballot as a candidate for both the House and Senate, Kennedy is not running for re-election to his House seat. Come January, there will be no one from the Kennedy clan in elected office.

The grandson of slain attorney general Robert F. Kennedy is part of the family’s fourth generation to carry the political torch, entering the House of Representatives in 2013.