Apparently, according to Charles Noble's book, The Collapse of Liberalism: Why America Needs a New Left. Noble, chair of the poli-sci department at UCLB, suggests that the Democratic party -- Wilson, Roosevelt, Johnson, Clinton, the whole nine yards -- has failed to challenge American capitalism in any meaningful way, and has equally failed to challenge the idea of American empire in any meaningful way. So the book contains a lot of sentences like these, "Since the Kennedy administration, American fiscal policy has emphasized cutting taxes rather than substantially increasing spending on needed public purposes."

Fair enough, but Noble makes the same error that, say, many Nader voters do: it's easy to fault the Democratic party if you only focus on results. True, in its final form, Lyndon Johnson's War on Poverty, proved relatively piddling. Same with the New Deal (compared to, say, European welfare states). Same with Clinton's micro-initiatives. But pointing that out is very different from faulting the intentions of those Democratic leaders. The U.S., lest we forget, has a bipartisan government with a surfeit of veto points. This structure made it very easy for Bob Dole to scuttle Clinton's health care plan, even as the majority of Americans (and Clinton) wanted some form of universal coverage. Now I think you might be able to make a sophisticated poli-sci argument that a firebreathing progressive would get more accomplished as president, but you can't get there simply by tallying up Democratic failures and ignoring larger, structural explanations. (Noble does tackle structural reform later on, but focuses on empowering third parties at the voting booth rather than clearing up some of the excess inertia within the legislative process.)

Also, jumping a bit off point, but not too much, I think Paul Krugman had the right idea in this old review of J.K. Galbraith's The Good Society:

To be both a liberal and a good economist you must have a certain sense of the tragic--that is, you must understand that not all goals can be attained, that life is a matter of painful tradeoffs. You must want to help the poor, but understand that welfare can encourage dependency. You must want to protect those who lose their jobs, but admit that generous unemployment benefits can raise the long-term rate of unemployment. You must be willing to tax the affluent to help those in need, but accept that too high a rate of taxation can discourage investment and innovation. To the free-market conservative, these are all arguments for government to do nothing, to accept whatever level of poverty and insecurity the market happens to produce. A serious liberal does not reply to such conservatives by denying that there are any trade-offs at all; he insists, rather, that some trade-offs are worth making, that helping the poor and protecting the unlucky may have costs but will ultimately make for a better society.

All true, and left progressives would do well to find some way to make peace with this reality as well. All told, there's a productive place for both far-left movement -- as an important motivational device -- and liberal-realism of the Krugman variety. More recently, though, we seem to see the far-left movement attacking liberal-realism as "too centrist", while liberal realists attack the far left as "too stupid." Someone needs to coordinate better the "means" wing and the "ends" wing of the Democratic party.