WASHINGTON — Does Joe Biden have a comity problem?

One of the most pressing questions facing the Democratic candidates for president is how they plan to enact their biggest promises, especially after seeing Senate Republicans smother much of Barack Obama’s agenda.

Biden’s response is a nostalgic call to return to an era of cooperation and collaboration, suggesting he can either coax the GOP along or shame it into action.

“The fact of the matter is, if we can’t get a consensus, nothing happens except abuse of power by the executive — zero,” Biden said when pressed on the issue at a recent forum on poverty. “If you start out with the notion there’s nothing you can do, well, why don’t you all go home then, man?”

But to some Democrats, his argument — and a damaging follow-up the next day, when Biden talked up his ability in the 1970s to collaborate with segregationist senators to advance legislation — was more evidence of a broader criticism from liberals: that the 76-year-old former vice president is mired in the past and too eager for conciliation.

“This idea of comity is a relic, and massively misunderstands the political playing field of today,” said Adam Jentleson, who served as a senior aide to the Democrats’ former Senate leader, Harry Reid.

Senate Majority Leader Mitch McConnell, R-Ky., departs the chamber on Thursday. (AP Photo/J. Scott Applewhite)
J. Scott Applewhite / AP
Senate Majority Leader Mitch McConnell, R-Ky., departs the chamber on Thursday. (AP Photo/J. Scott Applewhite)

To Jentleson and some other Democrats, hoping for GOP cooperation is a path to a stalled presidency. American politics has grown ever more tribal, and hard-core partisans exert outsize influence in primary campaigns, threatening lawmakers who compromise and rewarding purists who breathe the hottest fire, including in the Senate.

Jentleson, who supports Sen. Elizabeth Warren for the Democratic nomination but is not working with her campaign, saw the partisan strife first-hand, noting that Republicans gained a big benefit. The GOP blockades culminated in the chance to install a conservative on the Supreme Court after the party refused to grant even a hearing to Obama’s nominee Merrick Garland.

House Speaker Nancy Pelosi (D., Calif.) now calls Senate Majority Leader Mitch McConnell (R., Ky.) “the grim reaper.” He embraces the moniker.

Even if Democrats win the White House, McConnell is likely to remain an obstacle, since Republicans have a strong chance to hold the Senate or at least keep enough seats to block legislation.

Given that reality, the Rev. William J. Barber asked Democrats who appeared at his Poor People’s Moral Action Congress this week how they would turn their biggest promises into reality.

In contrast to Biden, some have called for changing the rules.

Warren said she’d be willing to end the filibuster, the Senate rule that requires 60 votes out of 100 to advance most significant proposals, and which has already been abandoned for judicial nominations.

Proponents say the rule encourages bipartisanship and slows extreme ideas. Critics see it as an anachronism that lets a minority faction stop popular legislation.

"If we’re in the majority, and Mitch McConnell wants to block us on the kinds of things our country needs and the kinds of things they elected me and other people to enact, then I’m all for getting rid of the filibuster,” Warren said. “We have to be willing to get in this fight.”

Democratic presidential candidate U.S. Sen. Elizabeth Warren, (D., Mass.) speaks during a forum on Friday in Miami. (AP Photo/Brynn Anderson)
Brynn Anderson / AP
Democratic presidential candidate U.S. Sen. Elizabeth Warren, (D., Mass.) speaks during a forum on Friday in Miami. (AP Photo/Brynn Anderson)

South Bend, Ind., Mayor Pete Buttigieg has also called for that change, though many other Democrats running for president, including several senators, won’t go that far. Sen. Kamala Harris (D., Calif.) has said she would work around the GOP with executive actions.

Sen. Bernie Sanders (Ind., Vt.) says it will take a populist show of force.

“There will never be any real change in this country unless there is a political revolution, and that means that millions of people have got to stand up and fight and take on the corporate interests, the billionaire class, the 1 percent," Sanders said at the Poor People’s Congress.

Biden, however, reveres the Senate and its traditions. He argues that a strong president who gets along with opponents can coax cooperation from them. If that doesn’t work, part of leadership is to “shame” lawmakers by building public support for an agenda.

“You have to go out and beat these folks if they don’t agree with you, by making your case, and that’s what presidents are supposed to do. Persuade the public, move people,” Biden said earlier this month.

Some Democrats scoffed.

“You can’t shame McConnell. It would be dope to find a path to greater bipartisanship but this isn’t that path,” Alyssa Mastromonaco, a former Obama aide, tweeted in response.

A day later, Biden sparked a furor as he recalled how he was able to collaborate in the 1970s with segregationist Democratic Sens. James Eastland and Herman Talmadge. Critics saw that as more evidence Biden is out of step with today’s party.

Biden later stressed that he was making a point about being productive within the political process, even if it means finding common ground with people he strongly disagrees with. Many black lawmakers came to his defense, including Rep. John Lewis (D., Ga.), a civil rights hero. Lewis said Friday that leaders of that movement “worked with people and got to know people” that opposed them, including members of the Ku Klux Klan.

“We never gave up on our fellow human beings,” Lewis said.

Jentleson said Biden’s tactic has already failed. Democrats scored major gains in Congress in 2006 and 2008, and Obama came into office as a historic figure, but Republicans still refused most cooperation.

Several people who heard Biden at the Poor People’s Congress worried that his approach would result in half-measures.

“We’re going to need to leap forward, we don’t need to crawl,” said Lorna Charlton, 58, of Richmond, Va.

Compromise “maybe works on some small potatoes issues,” said Karim Sariahmed, 27, of Philadelphia. But “what will he be willing to trade to sort of claim that victory?”

Biden’s campaign believes that the Twitter commentariat doesn’t reflect the broader Democratic Party, and that regular voters hunger for less division. Numerous polls show that majorities want to see interparty cooperation, including one Pew Research Center survey released this week that found 65 percent of adults see compromise as “very important.”

Obstruction from the party out of the White House isn’t new, nor did it begin under Republicans, said Josh Huder, a senior fellow at Georgetown University who studies Congress. Senate Democrats worked to stop much of President George W. Bush’s agenda, he said.

He pointed to several medium-size measures enacted while Obama was president and Republicans held both houses of Congress, including a budget deal and a bill to speed up the development of medical treatments, as evidence that “there is more compromise than the public would be led to believe at the current political moment.”

But the kind of major proposals many Democrats are campaigning on, from health care to climate change, have little hope of passing a divided Congress. “Large-scale political wins for a president are likely off the table," Huder said.

On the hottest issues, there are too many incentives to fight.