Obviously there's been a lot of yelling about how progressives should "get tough" with the White House and congressional Democrats. For what it's worth, we always need to be tough with our elected representatives, but we need to be smart about it, too.
"Getting tough" sounds great, but what's the practical definition of "getting tough?" Stomping our feet and repeating Republican frames doesn't really do anything other than serving as a kind of weird catharsis. We need real leverage, and we don't have it (yet!) because the bulk of the votes in America are in the ideological middle.
We have to get tough and convince those voters in the middle that progressive policies are better. If we can do that, we can convince politicians who need those voters.
Meanwhile, and in a practical sense, it's about congressional votes.
The reason Lieberman, Nelson and others can "get tough" is that they're willing to allow good bills to be killed, and they know that progressives are unwilling to do the same. Healthcare reform is, in a way, "too big to fail" and they knew it. They were unscrupulous and indifferent enough to kill it if they didn't get what they wanted. So they calculated that they could get attention and goodies if they threatened to vote no. And the only way that carries leverage is that they were seriously ready to vote no.
So in the case of healthcare reform, if we had convinced, say, Sanders and Feingold to behave more like Lieberman and Nelson, and if they had threatened to walk away, the legislation would have pulled to the right in order to get Snowe and Collins to make up the difference. The opposite simply wouldn't work -- numbers are numbers. When Lieberman and Nelson threatened to walk, where would the additional two votes have come from? There weren't any more votes to be had on the left.
In the longer term, if progressive congress members continue to abandon the president, bills would still be passed and signed by the president. Work would still get done. But it would be entirely moderate/centrist legislation. Because if the progressives walk away without any electoral leverage, the middle will attain more power -- not less.
Here's another consequence of pushing too hard against President Obama. The progressive movement risks losing minorities who, for many reasons, identify with the president, and regard him as an icon and role model. Rightfully so. Minorities will still mostly vote Democratic, but if progressives are seen as unreasonable or unfair, minorities might not support, for example, primary challengers who are affiliated with an anti-Obama progressive movement. One of many, many, many reasons why teaming up with race-baiting teabaggers is such a profoundly bad idea, by the way.
Winning from the left is a delicate balance, and I've been repeating here and on Twitter that accountability is good, but suicide isn't. We have to convince without scaring. We have to push without tripping over our own feet.
Until we have real electoral leverage, we're more expendable than the ideological center. However, if, slowly but surely, we get incrementally progressive-ish legislation, the ideological balance in America will begin to move in our direction and we gain more leverage.