While alienation among Republicans has drawn more attention, given the fiery language of the race’s front-running celebrity, Mr. Trump, the anti-establishment mood on the left is just as intense and potentially just as consequential to the selection of a Democratic nominee.
Mrs. Clinton has tried to lift her declining poll numbers by highlighting endorsements from governors and lawmakers — but such establishment backing has yet to do much good. Vice President Joseph R. Biden Jr. could face the same anti-establishment headwinds if he enters the race, given his four decades in Washington, although allies believe he has the personal touch to win over angry Democrats. Mr. Sanders castigates “the entire political and economic establishment” regularly, by contrast, a message that has drawn 650,000 donors and huge crowds of fervent supporters, like the 20,000 people at his Boston rally on Saturday evening.
“Democrats are experiencing a taste of what Republicans experienced in 2010, when so-called Tea Party candidates ran against establishment favorites,” said Jennifer Duffy, who tracks Senate races for the Cook Political Report. “More progressive or anti-establishment candidates are jumping into Senate primaries, often at the urging of more progressive voters who are tired of the status quo and want candidates who will run on issues like income equity.”
The contested primaries extend to House races. In New Jersey, a 24-year-old Sanders supporter, Alex Law, is challenging Representative Donald Norcross, portraying him as a machine politician.
“Democrats have enjoyed watching Republicans fight among themselves for the last five years, but there are anti-establishment and ideological divisions in the Democratic Party that will grow larger in the years to come,” said Nathan L. Gonzales, editor of The Rothenberg & Gonzales Political Report.
The disaffection among Democrats flows mainly from three sources, according to interviews with voters and strategists. Disappointment lingers with President Obama over the failure to break up big banks after the Great Recession and fight for single-payer health insurance, among other liberal causes. Fatigue with Mrs. Clinton’s controversies endures, as does distaste with her connections to the rich. And anger abounds at party leaders for not pursuing an ideologically pure, economically populist agenda.