Sen. Russ Feingold's announcement, declining an '08 presidential run, is surely a disappointment to those who want a nominee that is not only willing to run on core liberal principles, but potentially able to articulate those principles in a way that appeals to the broad electorate.

No one in the rest of the prospective field appears likely to quickly fill that void. But there is an upside to that.

Which is that grassroots liberals can focus more of our time on articulating those principles ourselves, before the primary season heats up.

If we best use our newfound perches -- in the blogosphere and in liberal talk radio -- to define the liberal vision on our terms, and show that the public will embrace such a vision, we won't need to find a single perfect candidate. The candidates will come to us.

Ideally, we want a Democratic consensus on what the party's overarching principles are.

We don't want a divisive, soul-searching spectacle every primary season.

We want everyone singing off the same basic songsheet, so public knows what direction Democrats would take the country, and the eventual nominee will be in a strong position no matter who it is.

In a primary, Sen. Feingold would have elevated the debate and sharpened party principles. Hopefully, he, along with the rest of us, can still do the same.