(Washington, DC) In their new role as the House majority, the Democrats so far this year have shown overwhelming unity on legislative votes. There are some exceptions, though — and they mostly come from members of the big and decisive House Class of 2006 who prevailed last year in politically competitive districts and could face difficult re-election contests in 2008.

Those are among the findings of a CQPolitics.com study of voting behavior in the current 110th Congress, which includes the first Democratic-controlled House in a dozen years.

In particular, the study analyzes those votes that pitted most Democrats against most Republicans — known in CQ parlance as “party unity” votes. House Democratic lawmakers averaged a 96 percent party unity score in the first five months of 2007.

This degree of near-unanimity, in turn, has prompted Republican House campaign strategists to brand potentially vulnerable Democrats as “rubber stamps” for Speaker Nancy Pelosi, whom they describe as an out-of-touch liberal from San Francisco.

That line of argument echoes a contention Democratic candidates and leaders made during the 2006 campaign, when they lanced Republican incumbents as “rubber stamps” for President Bush, his unpopular administration, and the leadership of a 109th Congress controlled by Republicans.

Democrats, though, say that they are not pursuing a partisan agenda and are tackling issues that Republicans failed to address during their majority rule. At the beginning of this year, Democrats steered six signature pieces of legislation to House passage, including an increase in the minimum wage, that enjoyed broad support with the public and in some cases had ample backing from Republican members.

But the CQPolitics.com vote analysis underscores that some Democratic lawmakers, particularly the more centrist members of the freshman class, have been less party-line than others. Twelve of the 25 lowest party unity scores of House Democrats were registered by freshmen.

These 12 hold seats that were among the 30 captured from the Republicans last fall — and all but one represent districts that voted favored Bush for president in 2004.

The outlier in the group is Pennsylvania Rep. Patrick Murphy, whose district near Philadelphia narrowly went for Democrat John Kerry over Bush. Murphy also was the only one among the dozen Democrats who voted against a supplemental spending bill that continued funding the Iraq war but did not mandate a troop drawdown. Many Democratic liberals opposed this bill on the grounds that it did not include a timeline to redeploy troops from Iraq.

This is not to say that these dozen Democratic freshmen are iconoclasts. They side much more frequently than not with their party on votes that divided Democrats and Republicans. Even on Iraq, before voting for the “clean” war spending bill, all of them previously voted for legislation — subsequently vetoed by Bush — that made a reduction of U.S. troops in Iraq a condition to continue funding.

Some of the dozen Democratic freshmen with the lowest party unity scores in 2007 lean to the right on some social issues. Four of them were among the 14 Democrats who voted against a bill to expand the definition of “hate crime” offenses to include certain violent crimes against an individual because of race, religion, national origin, gender, sexual orientation, gender identity or disability. Three of them joined just 13 other House Democrats in voting against legislation to promote embryonic stem cell research.

CQPolitics.com below profiles these 12 Democratic freshmen, their districts and their locations, and the votes that have made their records occasionally contrarian. Each member is followed by his or her party unity score and rank in the House Democratic caucus as of June 1; the result of the 2006 House election in the district; and the result of the 2004 presidential election in the district.

Heath Shuler, North Carolina’s 11th District (West — Asheville)

• Party Unity Score: 82.9 percent (4th lowest)

• 2006 result: Shuler 54%, Rep. Charles H. Taylor 46%

• 2004 President: Bush 57%, Kerry 43%

Shuler, who takes conservative positions on some social issues, voted against the bills to promote embryonic stem cell research and to classify certain violent offenses as “hate crimes.” He also voted against a defeated bill, backed by 169 Democrats and two Republicans, that called for the full withdrawal of U.S. troops from Iraq within 180 days.

Jason Altmire, Pennsylvania’s 4th District (West — Pittsburgh suburbs, exurbs)

• Party Unity Score: 83.3 percent (6th lowest)

• 2006 result: Altmire 52%, Rep. Melissa A. Hart 48%

• 2004 President: Bush 54%, Kerry 45%

Altmire took culturally conservative and economically populist positions in winning election in the 4th, which includes suburbs of Pittsburgh.

Altmire voted against the Iraq troop withdrawal bill and was one of 13 Democrats who voted last month — during consideration of the fiscal 2008 defense authorization bill — to restore funding for ballistic missile defenses.

Christopher Carney, Pennsylvania’s 10th District (Northeast — Central Susquehanna Valley)

• Party Unity Score: 84.3 percent (8th lowest)

• 2006 result: Carney 53%, Rep. Don Sherwood 47%

• 2004 President: Bush 60%, Kerry 40%

Carney voted against the Iraq troop withdrawal bill and the hate crimes bill and was one of six Democrats who voted against a bill to give the District of Columbia full voting representation. He was also one of 29 Democrats who voted against an amendment to prevent the Pentagon from using funds appropriated for military operations in Iraq or Afghanistan to plan a military operation in Iran.

Joe Donnelly, Indiana’s 2nd District (North Central — South Bend, parts of Elkhart and Kokomo)

• Party Unity Score: 84.3 percent (9th lowest)

• 2006 result: Donnelly 54%, Rep. Chris Chocola 46%

• 2004 President: Bush 56%, Kerry 43%

Donnelly, who opposes abortion, was a rare Democratic vote against the embryonic stem cell legislation.

Donnelly also has bucked his party on some defense-related votes. He voted for the amendment to fully restore missile defense funds, and he was a rare Democratic vote against an amendment to require the Pentagon to report on its plans to deal with alleged terrorist detainees at Guantanamo Bay, Cuba.

Brad Ellsworth, Indiana’s 8th District (West — Evansville, Terre Haute)

• 2007 party Unity Score: 84.5 percent (10th lowest)

• 2006 result: Ellsworth 61%, Rep. John Hostettler 39%

• 2004 President: Bush 62%, Kerry 38%

Ellsworth, who leans to the right on social policy, voted against the embryonic stem cell and the hate crimes legislation. He was one of 14 Democrats who voted against legislation to increase estimated tax payments for persons with gross incomes of more than $5 million. He was one of 13 Democrats who voted last month against the conference report on the fiscal 2008 budget resolution.

Zack Space, Ohio’s 18th District (East — Zanesville, Chillicothe)

• Party Unity Score: 86.6 percent (11th lowest)

• 2006 result: Space 62%, Republican Joy Padgett 38%

• 2004 President: Bush 57%, Kerry 42%

Space emphasized ethics during a campaign in which he was overwhelmingly elected to replace Republican Bob Ney, whose political dominance of the district came to an end after he pleaded guilty to federal corruption charges and resigned his seat in 2006.

Last month, as the House considered an overhaul of lobbying laws, Space was one of 33 Democrats who sided with a Republican motion that demanded that the bill require lobbyists to disclose whether they had “bundled” donation checks for political action committees.

Baron Hill, Indiana’s 9th District (Southeast — Bloomington, New Albany)

• Party Unity Score: 88.4 percent (13th lowest)

• 2006 result: Hill 50%, Rep. Mike Sodrel 45%

• 2004 President: Bush 59%, Kerry 40%

Hill voted to fully restore ballistic missile defense funds and against the conference report on the Democratic-crafted fiscal 2008 budget resolution.

Tim Mahoney, Florida’s 16th District (South central — Port St. Lucie, parts of Port Charlotte and Wellington)

• Party Unity Score: 89.2 percent (16th lowest)

• 2006 result: Mahoney 50%, Republican Joe Negron 48%

• 2004 President: Bush 55%, Kerry 45%

Mahoney, who succeeded scandal-plagued Republican Mark Foley, voted against the Iraq troop withdrawal bill and to restore the ballistic missile funds.

Harry E. Mitchell, Arizona’s 5th District (Scottsdale; Tempe; part of Phoenix and Mesa)

• Party Unity Score: 89.3 percent (17th lowest)

• 2006 result: Mitchell 50%, Rep. J.D. Hayworth 46%

• 2004 President: Bush 54%, Kerry 45%

Among Mitchell’s breaks with the Democratic majority was his “no” against the conference report on the fiscal 2008 budget resolution. Mitchell was concerned about its impact on estate and capital gains taxes.

Patrick Murphy, Pennsylvania’s 8th District (Northern Philadelphia suburbs — Bucks County)

• Party Unity Score: 89.6 percent (18th lowest)

• 2006 result: Murphy 50.3%, Rep. Michael G. Fitzpatrick 49.7%

• 2004 President: Kerry 51%, Bush 48%

Murphy has one of the lower party unity scores, even though the Iraq war veteran has sided with Democratic liberals in his votes to mandate a speedy withdrawal of U.S. troops from Iraq. Of the 12 Democratic freshmen profiled here, Murphy was the only one who voted for a bill, rejected on a 171-255 vote last month, that would have required the withdrawal of U.S. troops and contractors in Iraq within 90 days of the bill’s enactment — and the completion of the withdrawal within 180 days.

Murphy also was the only Democrat in the dozen to vote against a war spending bill that did not include a troop withdrawal timeline.

But Murphy did break from his party when he was among the 33 Democrats who voted for a Republican motion to a lobbying bill that mandated that the measure require political action committees to disclose “bundled” contributions to candidates. He also voted against the conference report to the fiscal 2008 budget resolution.

Nick Lampson, Texas’ 22nd District (Southeast Houston and southern suburbs — Sugar Land, Pearland, part of Pasadena)

• Party Unity Score: 90.2 percent (21st lowest)

• 2006 result: Lampson 52%, Republican Shelley Sekula-Gibbs 42%

• 2004 President: Bush 64%, Kerry 35%

Lampson represents an energy-producing district in suburban Houston, and he was one of four Democrats who voted in January against his party’s proposed revision of a 2005 energy law that Democrats said was too generous to oil and gas companies.

Lampson also voted against the Iraq troop withdrawal bill and also has voted for a few Republican motions to “recommit” certain bills back to their associated committees for changes.

Gabrielle Giffords, Arizona’s 8th District (Southeast — part of Tucson and northern suburbs)

• Party Unity Score: 90.8 percent (25th lowest)

• 2006 result: Giffords 54%, Republican Randy Graf 42%

• 2004 President: Bush 53%, Kerry 46%

Giffords also was among the 33 Democrats who voted to effectively require that political action committees disclose “bundled” contributions to candidates.