I think Kevin Drum gets it mostly right on the Michael Walzer piece:

To a large extent, despite the triumphalism of the right, liberalism has won most of the big debates in this country. Sure, we've only gotten 80% or 90% of what we set out to get half a century ago, but it's hard to bring a lot of passion to the fight for the final 10 or 20%. The reason liberalism seems lackluster these days is that with the exception of the radical left, which is mostly ignored, garden variety liberals don't have all that much to complain about.

That's true, at least on an ideological level (I hasten to confine it to issues of ideology because, as the blogs prove, us garden variety liberals have found plenty to complain about). But I think we're dealing with a second dynamic here, which is that we're no longer allowed to complain, our real complaints aren't viable in political discourse. Increased government control and involvement in private life is, to a large degree, off-limits in the public debate. On the other hand, deregulation and privatization, the cornerstones of conservative philosophy, are wholly in-bounds. The result is that the right can push as hard as they want in pursuit of their goals, but the left has to pussyfoot and sneak around our ends.

Health care is an excellent example. Republicans have happily adopted Health Savings Accounts as their Big Idea, despite the fact that HSA's are an abhorrent invention that exists to shunt risk away from government, away from insurers, and onto the individual. Nevertheless, the idea is allowable in the debate. Liberals, on the other hand, are trying to figure out ever subtler ways to move the country towards government health care, as we're not allowed to do it publicly. Hence Kerry's catastrophic reinsurance plan, hence CAP's expansion of FEHBP, etc. But compared to the level of privatization HSA's represent, these are barely half measures. But we're scared to push for single-payer, scared to signal agreement with Kennedy's Medicare for All, scared to pursue the policies that we know are actually the most logical and effective for this issue.