The House GOP celebrated Independence Day a week late.

On Thursday, Republican lawmakers in the House declared their own sort of independence — from the tyranny of outside conservative groups, from Nancy Pelosi and from the chatter in Washington that their leadership team had lost control of their conference.

The vote on the farm bill — 216-208, with every green vote coming from Republicans — was an exceedingly rare event under Speaker John A. Boehner of Ohio, Majority Leader Eric Cantor of Virginia and Majority Whip Kevin McCarthy of California, not because they passed a bill but because they faced down the Club for Growth and Heritage Action for America and won — and did so without relying on a single Democrat.

The stakes hardly could have been higher for a leadership team that has suffered one stumble after another this year — with increasingly cocky groups talking openly of getting new leadership more to their liking and repeatedly working to undermine the leaders’ agenda.

Another floor defeat would have dealt a deep blow, particularly to Cantor, who took much of the blame for the defeat of the farm bill the first time around over his backing of a conservative amendment Democrats considered a poison pill, and who championed the plan to drop food stamps from the bill in a risky bid to win an all-Republican majority vote.

The alternative — going to the Democrats, hat in hand — would have been humiliating.

So the majority leader effectively put the hammer down as members returned from the Independence Day recess, dressing down five House chairmen, including Paul D. Ryan of Wisconsin, for voting against the farm bill the first time. Cantor told them that, as leaders of the conference, it was unacceptable for them to vote against the bill. They wouldn’t cross him again.

The same day, Republicans held their first whip count on the new strategy during Monday evening votes. The results weren’t encouraging.

According to one lawmaker familiar with the whip count, there were 150 to 165 Republicans in support of the revised farm bill. The leaders had lost votes.

But Cantor did not relent. He cleared his schedule and began the slog to 218.

Over the next few days, Cantor had dozens of conversations with individual lawmakers. Sources insist he did not twist arms but used the old-fashioned art of persuasion.

“He doesn’t work based on threats,” one Republican lawmaker said.

Still, one GOP aide said, “McCarthy plays the good cop; Cantor plays bad cop.”

On this bill the duo teamed up, and aides say Cantor and McCarthy work well together and have direct lines of communication. McCarthy’s whip staff even includes former members of Cantor’s whip staff.

Lawmakers said a major turning point for the bill was when Agriculture Chairman Frank D. Lucas of Oklahoma changed his mind and said he would support the split strategy.

Erica Elliott, McCarthy’s spokeswoman, said the victory was “the product of the hard work done by our entire leadership team, our whip team and the dedicated members of the Agriculture Committee, specifically Chairman Lucas.”

Cantor’s spokeswoman, Megan Whittemore, called it a team win. “Everyone in leadership and all the members of the committee, especially Chairman Lucas, deserve credit,” Whittemore said.

But one GOP lawmaker insisted the win was “two-thirds Cantor, one-third the strategy.” Dropping food stamps gave rank-and-file Republicans cover to vote “yes” to appease farm interests while being able to argue back home that they weren’t backing welfare.

But leaders faced another foe working against them — both Heritage Action and Club for Growth declared a key vote against the measure — while Democratic votes evaporated. Lawmakers, aides and strategists ripped into the groups as hurting their party’s cause.

“They don’t act like they’re interested in building a conservative movement that can win races and do things,” one GOP strategist said. “They play games that make them feel powerful but have the practical effect of lost seats and lost opportunities to enact a conservative agenda.”

Others got more personal.

“House conservatives have grown tired of being lectured on conservativism by an ex-Giuliani staffer who works for the organization that created Obamacare,” said a House leadership aide, needling Heritage Action CEO Michael Needham. “So many conservatives voting for the farm bill is the proof in the pudding.”

Heritage Action’s communications director, Dan Holler, said his group wants to have a debate on policy.

“We don’t want to have a debate with anonymous staffers making ad hominem attacks that Geoff Davis made two years ago,” Holler said. Davis, a former Kentucky representative, called out Needham two years ago in a dispute over his Heritage scorecard.

Other Republican aides, meanwhile, said members felt double-crossed by Heritage, which had pushed to split the bill in two only to oppose it anyway.

But Heritage says it is the Democrats who duped Republicans.

The group insists the product of a conference committee with the Senate will be a farm bill that is “more costly than the Senate-passed policies and those proposed by President Obama.”

It says breaking the “unholy marriage” between food stamps and the farm bill is only one component.

“If someone is willing to settle for what they would perceive as a field goal when the touchdown is right in front of them, that’s their prerogative,” Holler said. “But our decision is to score the touchdown.”

But even some of Heritage’s allies, like Rep. Marlin Stutzman of Indiana, say the group overreached. “Sometimes you just have to take the victory when it’s right in front of you and move forward and try to capitalize on it and next time we’ll fight other fights,” he said.

The floor victory for the GOP, however, may not translate into a broader political or policy victory. Democrats are convinced they can bash Republicans for failing to vote for food stamps and are increasingly confident that they will be able to prevent significant food stamp cuts in the end.

After all, Lucas suggested the likely result will be that the Senate’s far slimmer cuts to the program will be adopted in conference.

That was precisely Needham’s concern when he ripped the GOP leaders’ bill as “nothing more than a naked attempt to get to a conference committee with the Senate.”

For their part, Democrats also mounted an impressive whip operation. Not a single one voted for the split farm bill.

But in many ways, the impressiveness of the Democratic whip operation points to the impressiveness of the GOP operation.

“We were against all the outside forces, we were against all the Democrats who tried holding up the vote all day,” one GOP lawmaker said.

And they won.