House Democrats are finally playing hardball in their role as a minority party, putting the onus on Republicans to find the votes within their own conference to pass legislation.

Their newfound edge forced the GOP’s hand in the fiscal cliff showdown, helping bring down Speaker John A. Boehner’s “plan B” legislation as well as Tuesday’s failed GOP effort to amend the Senate-passed fiscal cliff deal.

The 112th Congress was full of instances where Democrats helped Republicans pass big-ticket items. On the debt ceiling deal, payroll tax holiday extension and other bills, dozens of Republicans defected, but the legislation still passed.

If House Democrats stay united in future battles, the dynamic could keep the focus on whether Boehner has control of his conference, which will shrink with the 113th Congress.

“No doubt, this is hardball. It’s an effort to take our votes and use them wisely, either to withhold or to give,” said Democratic Rep. Elijah E. Cummings of Maryland, the ranking member on the House Oversight and Government Reform Committee.

A Republican leadership aide predicted the newfound Democratic unity is a “fluke,” and there’s some reason to believe the circumstances of the fiscal cliff fight were unique.

And a Democratic leadership aide said that Boehner’s plan B bill was “such a farce” that it made it easy for Democrats to oppose.

Still, Minority Leader Nancy Pelosi, D-Calif., had proposed much of the same substance of plan B in a May letter to Boehner, making it seem on the surface that Democrats would be hard-pressed to oppose the bill.

Pelosi has told colleagues she was “95 percent certain” that no Democrats would have defected, had the plan B bill come up for a vote.

On that bill, the hurdle for 218 Republican “yes” votes was too high for Boehner, and he had to pull it from floor consideration, harming Republicans’ negotiating position in the process.

Regarding House consideration of the Senate fiscal cliff deal, Boehner decided he would only bring up an amended version of the bill if he had 218 Republicans on board, something made necessary in part because of Pelosi demanding an up-or-down vote on the Senate deal.

Cummings said he was “99.999 percent certain” that no Democrats would have defected on an amended version of the bill.

Broadly speaking, Democrats did not make things as difficult for the GOP majority as they might have in the 112th Congress, in part because of fears about the consequences of not helping major bills, such as the debt ceiling deal, pass the House.

“Yes, we could have played politics with those and let our country default on its debt,” a second Democratic leadership aide told CQ Roll Call in October. “We did it because it was the right thing to do for the country,” the source said, adding that Democrats won concessions in the process.

A third Democratic leadership aide said the newfound willingness to force Republicans’ hand on votes is part of a growing perception of many Democrats that Republicans aren’t faithful negotiating partners on major fiscal issues. “It’s clear they’re not interested in bipartisanship,” the source said.

President Barack Obama, in aggressively demanding new tax increases in any future negotiations in a speech Monday, has drawn the same conclusion, the source added.

Obama is vowing not to negotiate with Republicans on the pending debt ceiling increase, but some liberal Democrats are skeptical, believing he will eventually crack when faced with Republican intransigence.

Vice President Joseph R. Biden Jr. insisted in a closed-door meeting with House Democrats on Tuesday that Obama would hold firm, saying that pressure from the business community would force Republicans to fold.