SEIU's PAC, called They Work For US, is modeled on The Club for Growth -- an anti-tax lobby that keeps Congressional Republicans on a tight leash, Stern told me. The idea of the new PAC from SEIU -- the largest and most politically powerful health care union in America -- would be to go after Democrats who vote against their interests on economic issues.

Some Congressional Democrats -- including New Yorkers Greg Meeks, Joseph Crowley and Ed Towns -- have already sparked the union's ire by voting for free trade agreements and Republican-sponsored bankruptcy bills.

I asked him if his union's focus on Democrats was in conflict with the party's effort to take back the Congress this year.

"I don't want to take back the Congress, I want to elect people that make work pay," he said [full quote]. "Our union was the largest contributor to the Republican Governor's Association and the Democratic Governor's Association in 2004."

You can hear more from Stern here.

-- Azi Paybarah