Rep. Kevin McCarthy (R-Calif.) speaks during a news conference with fellow Republican leaders at the U.S. Capitol in 2010. (Chip Somodevilla/GETTY IMAGES)

Burrowed inside a windowless office on the first floor of the Capitol, a handful of Republican aides run an old-school political shop that uses small white sheets of paper to tabulate lawmakers’ positions on pending legislation. Those tallies are then used to figure out just how much more work they have to do to get a GOP bill through the House.

From that point on, however, this operation, run by House Majority Whip Kevin McCarthy (R-Calif.), is up against a modern political reality that makes the job more difficult for him than for anyone who has had it before.

Simply put, McCarthy can’t guarantee success, in part because party power is not what it used to be on Capitol Hill, especially for the GOP.

Promises of special projects in the home district — a bridge here, a road there — no longer exist as an enticement. Pledges of fundraising help often draw little interest in the age of super PACs, which can deliver huge sums to a favored campaign on a moment’s notice. Personal pleas for fealty to party leaders fall on deaf ears among a new generation of conservatives who often prefer to be more closely allied with external movement leaders than with House Speaker John A. Boehner (R-Ohio).

All these complicating factors were on full display this week as more than 60 Republicans opposed the House leaders, joining Democrats to defeat a five-year farm bill. The bill was crafted to address the conservative ethos that now controls the caucus. It cut food-stamp programs and eliminated some cash payments to farmers. But for most of those Republicans, it wasn’t conservative enough, and they were willing to let it die.

Breaking down the vote: See how your member of Congress voted on the farm bill

This has been a recurring theme during Boehner’s tenure atop the always-raucous House, but after Thursday’s failure, the stakes are higher.

Democrats took it to mean that pending immigration legislation would be more difficult to pass. Republicans agreed but suggested that was because they were double-crossed on the farm bill by Democrats who had pledged to provide enough votes to pass it but then reneged. Republican leaders now question whether they trust Democrats at all.

Partisan trust issues aside, the big battles ahead — from immigration to raising the federal debt ceiling — will once again test Boehner’s leadership team and put the spotlight on McCarthy’s whip operation as it tries to wrangle enough GOP votes to give House Republicans some leverage in those big fights.

McCarthy came to the whip’s job in January 2011 with as little experience as anyone who ever served in the post. He had been in the House for just two terms and had never been in the majority, not in Washington nor during his brief stint in the California legislature. His advertised skill set had been that of a political tactician, helping recruit many of the 87 Republicans who swept into office in the 2010 midterm elections and vaulted the GOP into the majority.

McCarthy was a key part of Boehner’s pledge to run the House in a less heavy-handed way than Rep. Nancy Pelosi (D-Calif.) did when she was speaker from 2007 through 2010, and differently than former representative Tom DeLay (R-Tex.), who adopted “the Hammer” as a nickname and a political persona during his eight years as majority whip.

Boehner practices something known as “servant leadership,” a management philosophy born in the 1970s and based on the idea that leaders should serve their institutions and listen to the lowest-level workers. Adopted from his friend Gov. Mike Pence (R-Ind.), servant leadership is the guiding principle of Boehner’s team.

Veteran lawmakers and former senior staffers, however, question whether the leadership team is tough enough with wayward junior members who don’t feel compelled to support the team approach. Few veterans question McCarthy’s ability to count votes, but they worry about the entire leadership’s ability to get the votes, to get people on the fence to fall in line. Sometimes, McCarthy’s counts are accurate, but the totals are not high enough.

The whipping process itself is little different from that instituted by DeLay 18 years ago when the GOP claimed the majority for the first time in 40 years, according to McCarthy aides and senior aides to rank-and-file Republicans. (McCarthy’s chief of staff worked for DeLay, and his chief floor adviser served under two other GOP whips.)

About a week before a key vote, McCarthy and a team of deputy whips fan out across the House floor with sheets of paper, instructing fellow Republicans to check one of five boxes indicating their position on a bill: yes, lean yes, undecided, lean no, no.

This is handled on a member-to-member basis, with no aides involved and no modern communications such as e-mail, text messages or social media. The sheets of paper are returned to McCarthy aides, who put all the answers into a database. Over the next few days, each member gets a follow-up with questions about his or her position. A chief of staff for a rank-and-file Republican said that his boss recently received a call from McCarthy within two hours of taking a position of undecided on a minor bill.

“This is a new era for a whip operation. There are none of the old tools available to sweeten legislation in order to garner votes, and that’s a good thing. That means that we are bringing forward the best policies to the floor. The whipping process is centered around making the argument for why these policies must pass,” Erica Elliott, McCarthy’s spokeswoman, said Friday.

When it came to the farm bill, there was no disappointment in McCarthy’s vote tally afterward, according to aides to Boehner and House Majority Leader Eric Cantor (R-Va.). Democrats were the problem, they said. The whip team had informed the other leaders they had 180 GOP votes for the traditionally bipartisan legislation, and that Rep. Collin C. Peterson (Minn.), the top Democrat on the Agriculture Committee, had pledged to deliver about 40 Democrats who would support the measure.

That would have been just enough to clear the 218-vote threshold for passage.

Republicans insist that their big mistake was in trusting Peterson. According to Democratic and Republican aides, no GOP leader talked to Minority Whip Steny H. Hoyer (Md.), who has a reputation as a straight shooter and a reliable vote-counter on the Democratic side.

Moments before the roll call on the farm bill — just when McCarthy’s staff was breathing a sigh of relief — Peterson informed GOP leaders that he didn’t have nearly enough Democrats after some conservative amendments had been added to the bill.

The vote failed, as 171 Republicans voted yes and 10 or so others decided to vote no, because its defeat was assured, in order to side with conservative groups opposing the bill, according to senior GOP aides. So both counts came up short.

Pelosi cast the defeat as a GOP failure and called it “major amateur hour.”

Even as they insist that their mistake was trusting Democrats, Republicans have come to accept how difficult it is to persuade 15 to 30 of their most conservative colleagues to support any measure that contains even the hint of compromise by their leadership.

That’s a reality that is sure to confront them again this year as they try to advance a Republican-only bill to increase the debt ceiling. Among the renegades are four members who voted so often against the leadership last year that Boehner and his team momentarily abandoned their “servant leadership” approach and removed the four from key committee posts. The move was widely seen as McCarthy’s doing, but it has done little to improve discipline.

Rep. David Schweikert (R-Ariz.), deposed from the Financial Services Committee, said recently that he and McCarthy are working on “relationship repair,” but that he has no intention of changing his voting behavior.

“It may be one of the best things that ever happened to me,” Schweikert said of the committee ejection, suggesting he has more freedom now than ever.