It's not a done deal yet. Remember, the Senate Dems are just stupid enough to think the electorate won't remember in 2012 (and beyond) if taxes DO go up, even if only temporarily. And even if they DO, the entrenched mentality too many of them have probably has them thinking they've got jobs for life even if they're caught in bed with BOTH dead hookers and live boys.
Hell, look at Barbara Boxer, Harry Reid, and Patty Murray if you want some examples.