39 House Democrats voted against H.R. 3962, the healthcare reform bill, while 1 House Republican voted in favor of reform. In all of this, there are several distinct categories.
Role of the Blue Dog Caucus

The Blue Dogs are a group of 52 fiscally conservative Democrats that is well organized with powerful co-chairs for administration, policy, and communication as well as a robust whip team that often works in opposition to Clyburn’s whip team. Blue Dogs are the deciding vote on nearly every committee, and are most of the margin of victory on any floor vote. The Blue Dog Caucus is critical to understanding U.S. House voting patterns.

Three of the four members of the caucus leadership (Herseth-Sandlin, Melancon and Shuler) were among the 39 Democratic votes against the bill. However, they refrained from whipping the vote, or releasing an official caucus position on the most recent House version. This was reflected in that 24 of the 52 Blue Dogs voted against the bill. There was not a united stance on the issue.

Running for Statewide Office

Artur Davis (AL-7)

Running for Governor of Alabama. It is a long-shot bid but certainly a hopeless one had he voted for reform.

Charlie Melancon (LA-3)

Will be challenging David Vitter for his Senate seat in 2010. Despite Vitter’s frequent jaunts to disreputable houses, polling shows that he will likely win re-election.

Stephanie Herseth Sandlin (SD)

Rep. Sandlin will almost certainly challenge either John Thune for his Senate seat or make a run for Governor of South Dakota. Either way, especially after supporting the stimulus package, she is better-off opposing the bill because even a bid for re-election in her at-large district is a state-wide race.

Low Margin of Victory (<10%)

Not many representatives win re-election with less than a 10% margin, and those who do tend to vote somewhat apprehensively in their next term. 9 of the 39 Democrats who broke ranks fell into this category. Those with * following their names won victories by 2% or less of the vote.

Scott Murphy* (NY-20)

Bobby Bright* (AL-2)

Frank Kratovil Jr.* (MD-1)

Walt Minnick* (ID-1)

Eric Massa* (NY-29)

Parker Griffith (AL-5)

John Adler (NJ-3)

Glenn Nye (VA-2)

Chet Edwards (TX-8)

Freshmen with Substantial Victories

Six of the Democrats who jumped ship were Freshmen who won by more than 10%. Although this is a substantial margin of victory, they are still working on name recognition and fundraising sources. Their incumbency advantage is still not nearly what it will be three to four years down the road. They have reason to fear losing a bid for re-election because (1) their margin of victory is soft since it was obtained in an election of massive anti-Republican voting trends and (2) because of an especially motivated conservative base. The potency of that base had been displayed just 4 days before in the Virginia Gubernatorial election where high Republican turnout led to an electorate that had selected McCain by a 53-46% margin, almost the exact reverse of the 2008 result.

John Boccieri (OH-16)

Larry Kissell (NC-8)

Harry Teague (NM-2)

Betsy Markey (CO-4)

Suzanne Kosmas (FL-24)

Michael McMahon (NY-13)

Sophomores with Substantial Victories

Given that both 2006 and 2008 were high-democratic turnout and change-based elections, there is reason for these three legislators to fear that their margins of victory would disappear in a 1994 style contest.

Travis Childers (MS-1)

Won as special election in 2008 and then a general election in the same year. His 11% margin of victory is somewhat troubling in the very conservative Mississippi 1st Congressional District.

Jason Altmire (PA-4)

Heath Shuler (NC-11)

Despite his powerful position within the House, Rep. Shuler is only a Sophmore Democrat in a close North Carolina seat that was last held by a Republican.

Targeted By NRCC

Six Democrats who opposed reform are neither freshmen nor sophomores, nor did they win by 10% or fewer of their district’s votes but are none-the-less on the list of seats targeted by the NRCC. All of these democrats are firmly entrenched and some might have been able to politically survive a vote for health reform. However, all of these democrats have gained stability through a record of deliberate moderation.

Jim Matheson (UT-2)

McCain won his district by 18 points. In a tough election year, Rep. Matheson is potentially vulnerable.

Ben Chandler (KY-6)

Ike Skelton (MO-4)

Won re-election by 32% of the vote but McCain won his district by 22%. His power in the House as Chairman of the House Armed Services Committee and a respected veteran statesman is unquestioned but his position at home is based entirely on his record of fiscal conservatism and political moderation.

John Barrow (GA-12)

Dan Boren (OK-2)

Rick Boucher (VA-9)

Was unopposed in the last election, so I’m sure that the NRCC will have some good options in the next election. His decision was almost certainly ideological.

Blue Dog Coalition Members

Ten of the Democrats who voted no on H.R. 3962 are not in even the most remote form of electoral jeopardy, have secure fundraising resources, have no immediate ambitions for higher office, and are members of the Blue Dog Coalition. These members voted based upon ideology.

Jim Marshall (GA-8)

Lincoln Davis (TN-4)

Allen Boyd (FL-2)

Tim Holden (PA-17)

Mike McIntyre (NC-7)

Collin Peterson (MN-7)

Bart Gordon (TN-6)
A 49% margin of victory in 2008 leaves Rep. Gordon very safe, with any remotely  reputable challenger scared off.

Gene Taylor (MS-4)

Also obtained a 49% margin of victory. Extremely safe.

Mike Ross (AR-4)
His vote was purely ideological.

John Tanner (TN-8)
Was unopposed for re-election in 2008 and has been seated since 1988.
Nutty Liberals

Dennis Kucinich (OH-10)
Only Ohio would send to congress a man so ridiculous that in his zeal for a single-payer healthcare system he would vote against a comprehensive health insurance reform package that includes a public option and outlaws denial of coverage for preexisting conditions and prohibitively priced premiums.

Brian Baird (WA-3)
Holding a safe seat, with secure fundraising resources and a high approval rating for President Obama, Baird voted against the bill because “we do not yet have reliable estimates of how this legislation will impact the premiums paid by people who already have insurance”. Baird is a liberal and probably reads CBO reports, so this is all very strange.