There are some, like Scheiber (written after the Lamont victory, unfortunately not publicly available anymore) who have argued that democrats can't compete on ideas, and therefore must use unions to pull all the weight they can. This from the article, which is unfortunately all I have to quote now.

Interest group liberalism is a lousy way to run a party. But it may be better than the alternatives.

This kind of pessimism never helps anything, and now we have an example why.

Plan eases rules on election ads
BY KRISTIN JENSEN
BLOOMBERG

The Federal Election Commission is considering easing restrictions on the ads that unions and industry trade groups can run before an election using unlimited and undisclosed donations.

Spurred on by an unusual coalition including the AFL-CIO labor alliance and the U.S. Chamber of Commerce, the FEC plan exempts grassroots advertising that mentions lawmakers...

The rules actually did end up staying the same, which is good, but the more interesting aspect of the situation is that here we have the unions actually siding with the corporations, against fair elections. This isn't the first time this has happened - on many more philosophical issues, they don't really have any problem toeing the corporate line. The reason is that they represent working people - not the unemployed, those out of the labor force, or any other larger group in society. They are an interest group, and shouldn't particularly be treated differently than any other.

The irony in declaring that we must support unions because we don't have any ideas is that by doing so we actually cut off the flow of new ideas. This would be like eating our stock of seeds instead of leaving them for next year's crops - good in the short term, but in the long term it makes things even worse.