Sen. Harkin was one of three Democrats to vote against The Deal.  I don’t know what motivated Bennet or Carper’s opposition but Harkin’s reasons are clear.  Here’s Harkin on the Senate floor on Monday on why a $250k threshold – nevermind a $450k threshold – for income tax increases is horseshit (emphasis added):

“If you make $250,000 a year, you’re not middle class. You’re in the top 2 percent of income earners in America…. If we’re going to have some kind of deal, the deal must be one that really does favor the middle class — the real middle class, those that are making 30, 50, 60, 70,000 dollars a year. That’s the real middle class in America. And as I see this thing developing, quite frankly, as I’ve said before, no deal is better than a bad deal, and this looks like a very bad deal the way this is shaping up.”

And a video interview with him here on standing up to attempted extortion by the GOP/Tea Party:

“I don’t give credit to anyone who’s a hostage-taker.  I don’t give credit to anyone who uses a minority position to thwart the will of the majority.  And that’s what the Tea Party is doing.  They’re bullying people.  They’re threatening senators…”

If you watch that video, you’ll also learn that he understands that raising the salary cap on Social Security will fix most of its funding problem.  I haven’t heard any other senator or congressman make that (simple) observation.   Why not?