Few House members seeking re-election next year will be as vigorously targeted for defeat by the opposing party as freshman Reps. Walt Minnick of Idaho and Anh “Joseph” Cao of Louisiana.
Minnick is a Democrat who represents a rural and strongly conservative district that gave Barack Obama just 36 percent of the vote in the 2008 presidential election. Cao is a Republican from a heavily black district in and around New Orleans that gave just one in four of its votes to GOP presidential nominee John McCain . . . .
On the 255 roll call votes that pitted most House Democrats against most Republicans — which CQ brands as “party unity” votes — Minnick backed the consensus Democratic position just 40 percent of the time. Cao agreed with the position held by most fellow Republicans 63 percent of the time.
The study shows that Democrats overall are highly unified, with a median party unity score of 98 percent. But party unity scores below the Democratic norm are common among junior members, such as Minnick, who face difficult challenges stemming from their districts’ usual partisan orientation.
Of the 20 lowest-scoring Democrats in the party unity study, 16 are serving either their first or second terms, and . . .  represent districts that voted for McCain over Obama for president in 2008. . . .
[F]reshman Alabama Rep. Bobby Bright is the next Democrat least likely to vote with his party’s majority, with a party unity score of 52 percent. Bright is a former Montgomery mayor who won an open-seat race in 2008 with just more than 50 percent of the vote in a district that gave McCain 63 percent for president. . . .
Other Democrats with the low party unity scores include Travis W. Childers of Mississippi (61 percent); Harry E. Mitchell of Arizona (63 percent); Heath Shuler of North Carolina (68 percent); Ann Kirkpatrick of Arizona (75 percent); and Glenn Nye of Virginia (75 percent). All five Democrats defeated or otherwise succeeded a Republican when they were first elected in either 2006 or 2008. . . .
Betsy Markey of Colorado, who represents a sprawling part of eastern and northern Colorado that has a mild Republican lean, has a 92 percent score — much higher than Minnick or Bright, but still lower than the Democratic median. . . .
New York Democratic Rep. Eric Massa , elected last year to represent the state’s conservative-leaning Southern Tier, has a 91 percent score. Tom Reed, the Republican mayor of Corning, on Wednesday announced a 2010 challenge to Massa. . . .
Of the 20 lowest-scoring Republicans, only Cao and fellow freshman New Jersey Rep. Leonard Lance are serving either their first or second terms.
Because of his district’s strongly Democratic-leaning demographics, Cao is the most vulnerable House member in either party. . . .
Several contrarian Republicans are thinking about seeking statewide office: Mark Steven Kirk of Illinois (76 percent), who is weighing a run for senator or governor; Michael N. Castle of Delaware (75 percent), who’s thinking about running for the Senate; and Jim Gerlach of Pennsylvania (72 percent), who’s considering a bid for governor. . . .
An independent-minded voting record has enabled Republican Dave Reichert , who represents Seattle suburbs, to narrowly win three elections in a district that is trending Democratic. Reichert’s 66 percent party unity score is the fifth-lowest among House Republicans. He’s expected to face a competitive race again in 2010.
Lance (74 percent), one of the eight Republicans who voted for the climate change bill, is one of three Republican freshmen from districts that Obama won in 2008. The others are Cao, the leading House GOP dissenter, and Erik Paulsen of Minnesota, who has a 91 percent unity score that aligns him much more closely with his party peers.
From CQ Politics (hat tip to Colorado Pols; raw data here).
The Colorado delegation pans out as follows:
Only 39 of the 178 House Republicans are as loyal to their party in party unity votes as the median House Democrat (i.e. 98%). The median Republican U.S. Senator is 95% loyal to his party. The median Democratic U.S. Senator is 92% loyal.
Name District Presidential support Party unity
Diana Degette CO1 99 97
Jared Polis CO2 87 98
John Salazar CO3 88 95
Betsy Markey CO4 88 92
Doug Lamborn CO5 15 99
Mike Coffman CO6 38 96
Ed Perlmutter CO7 96 96
Mark Udall CO 97 94
Michael Bennet CO 97 91
John Salazar, despite having an independent reputation as a Blue Dog, is more loyal to the President and to the Democratic party in his voting than I would have expected.
Democratic party power in Congress is strong, but not absolute. While Democrats have large majorities in both houses of Congress, many moderates in Congress from both parties, in response to the concerns of their constituencies, often do not vote the party line.
Democrats have 257 out of 435 seats in the House of Representative (218 is a majority and there are no filibusters in the House). Thus, Democrats in the House can lose 39 votes from their own ranks, without gaining any, and still pass legislation. Ranked by party loyalty, the Democrat needed to cast the 218th vote on a measure votes with the party on party unity votes about 90% of the time. Democrats do not have the two-thirds majority in the House necessary to expel members from the House, override a veto, or propose constitutional amendments without bipartisan support.
In the U.S. Senate, Democrats have 60 out of 100 seats including two independents who caucus with the Democrats, one is socialist Bernie Sanders and the other conservative leaning independent Joe Lieberman (51 seats is a majority and 60 voters are needed to break a filibuster). But, both Olympia Snowe (44% loyalty) and Susan Collins (49% loyalty), the Republican Senators from Maine, both vote with the Democrats more often than they do with the Republicans on party unity votes and support the President more often than some members of the Colorado Democratic Party delegation.
Democrats in the Senate need all hands on deck to pass legislation facing a filibuster (and marginal Democrat Arlen Specter votes with the Democrats just 49% of the time), but can lose 9 votes on a bill that is not filibustered. Ranked by party loyalty, the Democrat needed to cast the 51st vote on a measure votes with the party on party unity votes about 86% of the time. Democrats do have the two-thirds majority in the Senate needed to pass impeachments, expel members from the Senate, override a veto, propose constitutional amendments, adopt treaties or change Senate rules without bipartisan support.
A Democratic Party President means that few vetoes are expected that need to be overridden.
Republicans, of course, need bipartisan support to do anything.