Democrats have long lamented that they do not enjoy the kind of enthusiasm which Republicans benefited from with the rise of the tea party.

The left has gone to great lengths to manufacture this sort of energy, including touting the volatile Occupy Wall Street movement as a rough tea party equivalent. Though some have fretted that tea party’s downsides – the targeting and ousting of electable Republican candidates – would necessarily follow the ascension of a liberal version of this grassroots movement to prominence.

Democrats got lucky, in a fashion, when it became clear that the Occupy movement had no interest in electoral politics. “Many occupiers believe it’s futile,” Mother Jones columnist Josh Harkinson wrote in 2012, “because they’d never win against an avalanche of unregulated corporate political spending.” In sacrificing some enthusiasm from an energized Occupy base, Democrats gained stability which has arguably served them well… Until now.

The key combustible element which Democrats always lacked that serves to catalyze the formation of the tea party is a lack of power. This month, Democrats finally lost control of the Congress after maintaining leadership authority over at least one chamber for the last eight years. Republicans enjoy their largest majorities in the Congress in the post-war period. As was the case for Republicans in 2009, the remaining Democratic caucus is beholden to liberal constituencies that are far less interested in compromise.

As Politico reported on Tuesday, this has created an interesting reversal of fortunes in Washington. Republicans are no longer the “hell-no” caucus, as Politico’s Burgess Everett reported, will be a liberal one.

Everett noted that the defeat of the Keystone Pipeline in the Senate on Tuesday by one vote marks the start of a revolt against the leadership style of Harry Reid (D-NV), who has sought to protect his vulnerable members with similar maneuvers in the past. It foreshadows a contentious future for congressional Democrats.

And while the “hell-no” caucus plans on taking the fight to Republicans in the near future, the more immediate battles are with the centrists in their own party. Sound familiar?

Progressives are girding for battle with Republicans over campaign finance law, consumer protections and women’s health care. But the early battle lines appear increasingly drawn around environmental policy, where Democratic centrists may defect from leadership in next year’s Senate and help Republicans pass legislation strongly opposed by liberal senators

With Republicans able to steamroll Democrats in the House with a historic majority, next year’s Senate Democratic minority becomes the last line of congressional defense for liberals and progressives. And as the GOP plans its agenda, members of the party’s left wing are vowing that there’s still fight left in them despite their diminished influence: If provoked, they say they are ready to use Senate procedure to fight the majority’s agenda tooth and nail.?

Indeed, Whitehouse and other progressive senators said that while other economic and social issues worry them, they don’t believe the damage that Republicans could do by unwinding environmental regulations can be undone. Given that sense of urgency, climate change may be the issue that draws the strongest challenge from an increasingly influential bloc of Senate liberals as Republicans prepare to take both chambers of Congress for the first time in eight years.

“Even as they vow to fight Republicans at every turn on issues that fundamentally divide liberals and conservatives, left-leaning Democrats insist that they will not do so seeking retaliation against a Republican minority that stymied their economic, environmental and social priorities for so long with filibusters and delay,” Everett concludes. Those days, they insist, are gone — leaving liberals to somehow find a balance between fighting for their convictions and not drawing the same charges of obstruction that have dominated Democratic messaging for years.”

Grassroots Democrats are unlikely to enjoy that sort of accommodation with Republicans. And, just like the tea party, leftwing challengers will emerge to oust the “squish moderates” in their midst. The Democratic Party is in for a bumpy ride.