They led the most powerful forces in healthcare -- the trade groups representing doctors, insurance companies, hospitals and drug makers. Any one of them could stall, if not derail, President Obama's hopes of overhauling the U.S. healthcare system. Instead, they stood with Obama before TV cameras at the White House and pledged their cooperation. For Obama, the show of unity gave momentum to perhaps his most ambitious domestic goal. But the moment was a victory, as well, for another man invited to the event that morning in May. Andy Stern heads the SEIU, the union that helped corral the industry...