Megan McArdle, frequently in error but never in doubt:

I think that ramming through the bill on a party line vote makes it very likely that the Democrats will lose the house in 2010; the American public doesn't like uniparty votes, especially on something this controversial.  A lot of liberals have gotten angry at me for saying this, but it's not a normative statement; it's an observation.  IF the Republicans had been willing to push forward on a controversial bill with no Democratic cover, we'd have private social security accounts right now.  But they weren't, for a reason.

To support her "observation" that Americans hate party-line votes, McArdle cites one data point: Republicans could have privatized Social Security in 2005 but declined because they feared a public backlash. First of all, I'd point out that this isn't really evidence that Americans hate party-line votes, it's evidence that the Republican Party in 2005 thought Americans hated party line votes. Second, it's completely untrue that Republicans could have changed Social Security on a party line vote. They had only 55 Senate seats, five short of the number required to break a filibuster. Nor could they have used the reconciliation procedure to enact reform with just 50 votes -- the rules of the Senate explicitly forbid using reconciliation to change Social Security.

Are there any examples of Americans recoiling from a party line vote qua party line vote? McArdle offers none. The 1993 budget deal was unpopular, though I suspect the content of the bill (spending cuts and tax hikes) was more responsibile for its unpopularity, and several other factors contributed more to the Democrats' 1994 electoral failure. Cutting against McArdle's case is the 1990 budget deal, which was substantively similar to the 1993 deal and also unpopular, but extremely bipartisan in character.

I think that a couple months ago, Democrats would have paid a fairly high price for passing a health care bill with zero or one Republican votes. This is because the major theme of the news coverage revolved around whether Democrats would find a bipartisan solution (wonderful!) or go it alone (boo!) August, as I have argued, may have actually helped Democrats. Before, Republicans were making earnest-sounding pleas for negotiation and bipartisanship while slowly bleeding out the calendar. The recess furor exposed (and helped create) the GOP's total unwillingness to compromise. The result, I suspect, is that Democrats will now pay a far lower price for passing a bill without substantial GOP buy-in.