There Is a Revolution on the Left. Democrats Are Bracing.

“They need to wake up and pay attention to what people actually want,” Ms. Conner said of Democratic leaders. “There are so many progressive policies that have widespread support that mainstream Democrats are not picking up on, or putting that stuff down and saying, ‘That wouldn’t really work.’”

.. Energized to take on President Trump, these voters are also seeking to remake their own party as a ferocious — and ferociously liberal — opposition force. And many appear as focused on forcing progressive policies into the midterm debate as they are on defeating Republicans.

.. Fifty-three of the 305 candidates have been endorsed by the Justice Democrats, the Working Families Party, the Progressive Change Campaign and Our Revolution, organizations that have helped propel challenges to Democratic incumbents.

.. Mr. Brewer, who backs Gretchen Whitmer, a former State Senate leader and the Democratic front-runner for governor, said Michigan Democrats were an ideologically diverse bunch and the party could not expect to win simply by running far to the left.

“There are a lot of moderate and even conservative Democrats in Michigan,” Mr. Brewer cautioned. “It’s always been a challenge for Democrats to hold that coalition together in the general election.”

.. The pressure from a new generation of confrontational progressives has put Democrats at the precipice of a sweeping transition, away from not only the centrist ethos of the Bill Clinton years but also, perhaps, from the consensus-oriented liberalism of Barack Obama. Less than a decade ago, Mr. Obama’s spokesman, Robert Gibbs, derided the “professional left” for making what he suggested were preposterous demands — like pressing for “Canadian health care.”

.. urged Democrats to recognize the intensity of “anger, fear and disappointment from people in our own party,” especially those new to the political process.

“They’re young, and a lot of them are folks that weren’t around or weren’t engaged when Obama ran for the first time,” Mr. Johnson, 36, said. “So this is their moment of: Let’s take our country back.”

.. primary voters have chosen candidates who seem to embody change — many of them women and minorities — but who have not necessarily endorsed positions like single-payer health care and abolishing the Immigration and Customs Enforcement Agency.

..  Martin O’Malley of Maryland, a left-of-center Democrat who ran for president in 2016, suggested the party wants “new leaders and fresh ideas” more than hard-left ideology.

“Sometimes that may be filled by a leader who calls herself a Democratic socialist, and sometimes it’s not,” said Mr. O’Malley, reflecting on the political convulsion that touched his home state. “Sometimes it’s with a young person. Sometimes it’s with a retiree. Sometimes it’s with a vet.”

.. avowedly moderate standard-bearers, such as Senator Doug Jones of Alabama and Representative Conor Lamb of Pennsylvania

.. among Democratic stalwarts, there is a sometimes-rueful recognition that a cultural gulf separates them from the party’s next generation, much of which inhabits a world of freewheeling social media and countercultural podcasts that are wholly unfamiliar to older Democrats.

.. But within deep-blue precincts where Democratic insurgency appears strongest, talk of accommodating the center is in short supply.