There were 34 Democrats who voted against Obamacare in 2010: Here
21 lost, 7 retired
Realizing that the ACA was based on a conservative framework, and that it clearly would be desired by Republicans and so-called Conservative Democrats in a less partisan world, these Democrats should have voted their conscious, took the political support available to defend their vote, and been honorable legislators. I say this because I'm sure had Republicans worked with the President in good faith, the new law could have been pretty much the same, and these same people would have supported it. If you notice, Senate Democrats did just fine. President Obama did just fine. The House members who voted for Obamacare did just fine. Now years later, we're in a situation where the opposite of what was predicted is true. If you're a Democrat, and you voted against Obamacare you're in trouble. The Republicans will attack you anyway, and Democrats don't want you.