Guess what? It wasn't the Tea Partiers

House freshmen have been caricatured as the face of Republican intransigence in Congress, portrayed as a diverse and cacophonous mob standing in the way of Republican leaders and legislative compromise.

But an analysis of voting patterns on the most contentious bills in the 112th Congress shows that House members of the Republican Study Committee — a group of both veterans and newcomers that meets weekly to hammer out a conservative agenda — have cast the bulk of “no” votes on big bills, including those important to Speaker John A. Boehner of Ohio.

The freshmen who have joined the study committee — which was founded in 1973 — play an important role in its renewed clout, having increased its membership to 163 from roughly 110 two years ago. As a group, however, the freshmen are less homogenous and less apt to buck the leadership than the study committee itself is as a whole.

In the surprising failure of a bill early last year to extend provisions of the Patriot Act, 18 (or 69 percent) of the Republicans who rejected the measure were committee members and only 9 (35 percent) were freshmen. In a defeated spending measure that included disaster aid for states pounded by tornadoes, 94 percent of the 48 Republican “no” votes came from committee members and only 40 percent from freshmen.

“A lot of people think it’s freshmen,” said Representative Kevin McCarthy of California, the House whip, whose job it is to persuade members, using pizza, pressure and occasionally spleen, to take tough votes. “It’s not. It’s older members.”

It was founded in 1973 by Paul Weyrich and other conservative activists to keep a watch on the House Republican leadership, which they saw at the time as too moderate. Their formation mirrored the rise of the Democratic Study Group, a liberal force in the House Democratic Caucus founded in 1948. The group's first chairman was Phil Crane of Illinois. The group briefly dissolved in 1995 after the Republicans won control of the House for the first time in 40 years.

However, it was almost immediately refounded as the Conservative Action Team by Dan Burton of Indiana (the last chairman of the original RSC), Sam Johnson of Texas, John Doolittle of California and Ernest Istook of Oklahoma. The four founders alternated as chairmen throughout the next two Congresses until David McIntosh of Indiana became chairman in 1998. When he resigned from the chairmanship in 2000 to focus on his run for governor of Indiana, Johnson reassumed the chairmanship. John Shadegg of Arizona became chairman in 2001, renaming it the RSC soon after taking over. Shadegg increased the group's membership from 40 members in 2001 to 70 members in 2003. Sue Myrick of North Carolina was the first woman to serve as chair from 2003 to 2005. Mike Pence of Indiana served as chairman from 2005 to 2007 and Jeb Hensarling of Texas served as chairman from 2007 to 2009. Tom Price of Georgia who succeeded Hensarling in 2009. After the Republicans regained control of Congress in the 2010 elections, Jim Jordan of Ohio was elected chairman of the RSC.

Several members of the RSC have held high positions in the House leadership. Presently, seven of the nine top Republican leaders—Majority Leader Eric Cantor, Chief Deputy Whip Peter Roskam, Conference Chairman Jeb Hensarling, Conference Vice-Chairwoman Cathy McMorris Rodgers, Conference Secretary John Carter, Policy Committee chairman Tom Price, and National Republican Congressional Committee chairman Pete Sessions--are members of the RSC. Only two members of Republican leadership are not members of the RSC: Speaker John Boehner (who is, by tradition, the leader of the House Republicans) and Majority Whip Kevin McCarthy.

The organization has long had ties to outside groups closely allied with the most conservative elements of the Republican Party, such as the National Rifle Association, The Heritage Foundation, Focus on the Family, Concerned Women for America and the conservative magazine National Review, as well as the libertarian Cato Institute.

Last week, Mr. Boehner told Peggy Noonan, a conservative columnist for The Wall Street Journal, “My problem is with a few senior members who, they always want more.”

On measures to continue financing the government and raise the debt ceiling — in which a government shutdown and default were narrowly averted — freshmen Republicans provided more than half of their party’s “no” votes just once, while committee members routinely provided 70 percent to 100 percent of opposition votes.