Now, some House legislators are preparing for calls to push through an ambitious agenda in a democratically controlled Washington or face another wave of primary elections. Some of them may retire or, should Joseph R. Biden Jr. win the presidency, accept administrative posts instead of running for re-election.
Still others will surely try to imitate Mr. Markey who made it Channeling the new activism on the left. He was first elected to the House of Representatives in 1976 and was a fairly reliable Liberal vote in the House and Senate, where he moved in 2013 after John F. Kerry became Secretary of State.
However, he has taken a leadership role on environmental and technology-related issues, which linked him to perhaps his most important supporter: Ms. Ocasio-Cortez. Their joint authorship of the Green New Deal gave Mr. Markey not only access to their support, but also access to a new generation of environmental activists. He garnered early support from the Sunrise Movement, the environmental activist group, and formed a strong coalition among young progressives.
“If we want a planet that people of my generation can live on, we need someone like Senator Markey,” said Lindsay Aldworth, 29, who attended the Sunrise Movement in college and attended a rally for Mr. Markey in New Bedford, Mass., Last week.
That excitement frustrated Mr. Kennedy, who was counting on winning votes from young voters. He believes the state’s many white-liberal voters did not blame Mr. Markey for some of his previous positions, including his long-ago disapproval of Boston public school integration, as they did with Mr. Biden.
However, Mr. Kennedy had formed his own support coalition, backed by a number of voters of colored and workers across racial lines.