A very interesting discussion has broken out between two titans of the polling-analysis business, Mark Blumenthal of pollster.com and Nate Silver of fivethirtyeight.com. Nate has been exploring the theory (beloved of some Obama critics in the blogosphere) that the President’s rhetoric of bipartisanship on the economic stimulus legislation has blurred his message even as rank-and-file Republicans move decisively against him, producing net losses in his approval ratings without producing any offsetting benefits. Mark responded with alternative explanations of the slight drop in Obama’s approval ratings as entirely predictable, and suggested that a more partisan approach might have worsened them significantly.
Here’s the nut graph of Mark’s argument:

[Is there] evidence of the limits of bipartisanship? Let’s remember that Obama holds an overall approval rating that most polls now peg in the mid-sixty percent range, after winning with 52.9% of the votes cast. Doesn’t the aggregate approval rating, including approval from roughly a third of Republicans, say something about the benefits of the “bipartisan” messaging? And how will those Republican and Republican leaning independents respond to harsher partisan rhetoric from the President?

(It’s worth noting that the most recent Democracy Corps poll also found a third of Republican voters supporting Obama’s “policies and goals”).
Nate’s response adknowledges that there’s no way to definitively answer the question of Obama’s more partisan path-not-taken. But in terms of the path he did take:

[As] Mark points out, most of the decline in Obama’s approval ratings has come from Republicans, among whom he has lost a net of about 24 approval points (approval rating less disapproval rating) in two weeks. This is in spite of the fact that by roughly a 2:1 margin, Republicans think that Obama is in fact working in a bipartisan fashion, according to the latest CBS News poll.
In other words, there are quite a lot of Republicans who believe that (i) Obama is in fact governing in a bipartisan manner but (ii) disapprove of his performance anyway. Republicans can appreciate Obama’s civility — but still disagree with every piece of his agenda.

More pointedly, Nate suggests that Obama really doesn’t need rank-and-file Republican support to keep his approval ratings at a positive level. His conclusion:

[The} value of maintaining the appearance of bipartisanship does not appear to be all that high if it gets in the way of persuasion. For a week or so there during the stimulus debate, we were getting a lot of the former from the White House, but not so much of the latter.

This appears to put Nate at least generally in the camp of those who applauded the President’s speech to the House Democratic Caucus last week, and his press conference last night, as a sign that a chastened Obama has largely gotten over all the bipartisanship claptrap and is finally delivering a clear progressive message that will attract anyone who is genuinely persuadable.
As it happens, I’m among those who also have applauded Obama’s most recent speeches, but for a somewhat different reason than those articulated by most progressive bloggers. He’s distinguishing cooperation with “Republicans” (or perhaps more accurately, non-Democrats) from accomodation of conservative ideological attacks on his agenda, which in turn he’s identifying with the failed Bush policies of the past, and with business-as-usual in Washington. To put it another way, he’s seeking to identify those who are outside of (or shakily committed to) his November 4 coalition who are actually persuadable, and separating them from the GOP, whose obdurate opposition to the stimulus package is actually a good thing in terms of expanding the Democratic Party.
And this is why despite my enormous respect for Nate Silver, I think he’s got one conclusion almost backwards when he says:

While Obama certainly needs the support of a couple of Republican senators to pass his agenda, he doesn’t necessarily need the support of Republican voters.

In terms of his long-range goals, Obama’s ability to influence a significant minority of Republican voters–and even more importantly, of Republican-leaning independents–is of greater value, and comes at a lower cost, than efforts to drag more than one or two Republican senators across the line on specific legislation. Such broad support outside Washington, if it is maintained, will either create great pressure on at least some Republican members of Congress to behave themselves, or if they don’t, will help alienate potentially Republican voters from the GOP. This is what I’ve called “grassroots bipartisanship,” and looking beyond the stimulus bill to future fights over health care and other key issues, and to the next two election cycles, it remains a pretty good strategy for Obama.
That doesn’t mean that Obama has done everything right during the stimulus debate: he often didn’t make the distinction between grassroots Republicans and independents and conservative ideologues in Washington very clear; the Gregg and Daschle cabinet controversies interfered with his message and embroiled him in what looked like conventional Beltway politics; and all the attention being paid to the “centrist coalition” in the Senate also helped make the final legislation look like the produce of High Broderist deal-cutting. You can also make the case that the administration’s handling of the latest phase of the financial industry “rescue” looks dangerously a lot like the handling of the first phase by the Bush administration, which the general public strongly disliked.
But all those missteps were potentially damaging not because they involved “bipartisanship,” but because they imperiled the President’s ability to stand for a large-majority, supra-partisan coalition around the country seeking to force change on Washington.