After John Edwards stepped out yesterday, and endorsed Senator Obama, the debate immediately began about whether his endorsement would matter, or what it would mean for Obama. It’s meaning a lot to Obama today.

Obama has picked up four of Edwards’ delegates, and the powerful endorsement of the United Steelworkers. Today, the Steelworkers, who had endorsed Edwards last year, announced thier endorsement of Obama. Their endorsement was highly courted in this election by Senator Clinton and Senator Obama. 

United Steelworkers: “Senator Obama’s call for a significant change of direction amounts to far more than a compelling rallying cry.  It is buttressed by his record of consistent support for workers, by his call for sweeping changes to our health care system, by his unflinching support for Employee Free Choice, and by his insistence that America’s trade policies must, first and foremost, serve the interests of America’s working families.

So, what does this mean for Obama? It means that Obama might not have a problem with some of the “working class votes” in the fall, like so many of the pundits have been debating about non-stop in the last 48 hours.

The steelworkers have roughly 600,000 members, and many reside in Pennsylvania and Ohio, which are two critical states in the general election for the Democrats. Alex Conant, spokesman for The Republican National Committee, didn’t waste time responding to the Steelworkers endorsement.

Conant said: ”Big union endorsements are no substitute for Obama’s serious lack of experience and understanding of economic policy. Obama’s poor judgment on economic matters would result in higher taxes on rank-and-file union members and hurt job creation. Americans looking for strong economic leadership won’t find it in Obama’s tax-and-spend agenda.”

I think this big union endorsement matters, and I suspect more endorsements to follow. I interviewed some members of United Steelworkers Union Local 5032 in Pennsylvania prior to the primary. You can read about thier story here.