There are quite a few good articles about the future of the labor movement in the latest issue of Social Policy. You have to register to read them, sadly, but it's free and not too much of a hassle. Many of the articles are more technical, about the nuts and bolts of organizing, but one point by Mari Matsuda of Georgetown strikes me as an important, if subtle, one:

[We need to] develop a working theory of homophobia as a tool of class oppression, and an organizing strategy to counteract it.

I don't know if a "working theory" is really what's needed here, but it is true that homophobia and homophobic appeals, especially within the ranks of labor, have created similar, if somewhat smaller, obstacles to organizing as racism did back in the '40s. And as Matsuda reminds us, the labor response back then was swift and unyielding: "When my father was a steelworker in Chicago, he saw grown men weep when they were voted out of a union they would die for because they could not let go of the racism they thought they needed." That's a lesson worth noting. The idea that strict economic populism can somehow "overcome" an unpopularity on social issues is, I think, a misguided one.