From the Wall Street Journal:
With congressional proposals already stirring raw emotions, few supporters are eager to add the incendiary issue of illegal immigration. A provision in the House's health-care-overhaul bill rules out federal funding for illegal immigrants.
But in many ways, illegal immigration is at the nexus of two key health issues: the uninsured and ballooning costs.
Roughly half of the 12 million illegal immigrants in the U.S. don't have health insurance, according to the Pew Hispanic Center, a nonpartisan research group. Like others who can't afford medical care, illegal immigrants tend to flock to hospital emergency rooms, which, under a 1986 law, can't turn people away, even if they can't pay. Emergency-room visits, where treatment costs are much higher than in clinics, jumped 32% nationally between 1996 and 2006, the latest data available.
(The other half get their insurance through identity theft.)