To mark the second anniversary of President Obama's health care overhaul, voters should turn to his home state of Illinois to see how it will deliver on its promise of quality health care for the most vulnerable. When they do, they will probably not like what they see.

As a state senator, President Obama sponsored and supported large expansions of the state's Medicaid program, similar to the ones in his national health care reform bill. These expansions have led to worsening care for the very people Medicaid was meant to protect.

Illinois' Medicaid program is on the verge of collapse. Well-intentioned program expansions have ballooned enrollment to more than 3 million people. The program reimburses doctors so poorly that many simply cannot afford to take more Medicaid patients.

And the costs of expanding the program have become so great that Illinois is now billions of dollars in debt to doctors and hospitals, who find themselves waiting months or even years for reimbursement. As a result, more and more doctors are posting signs in their offices that say they will not see Medicaid patients.

Illinois' problems were so bad that in 2005, a federal judge ordered the state to study the access barriers the Medicaid program has created. The results of that study, recently published in the New England Journal of Medicine, found that children with throat cancer have only a one-in-three chance of seeing a specialist if they're enrolled in Medicaid. For those with juvenile diabetes or epilepsy, the odds of seeing a specialist are one-in-two. Worse yet, even when the children can get an appointment, they are forced to wait several months for it. For these sick kids, those months can be the difference between life and death.

The president's health care reform will only make these problems worse. Instead of reforming the underlying problems in Medicaid, his health care overhaul simply expands the program to more people -- and forces them to compete with the others for appointments with fewer and fewer doctors willing to participate. When millions of new enrollees are dumped into the system, the poorest, who have nowhere else to turn, will suffer most.

It is a noble goal to deliver quality health care to the most vulnerable -- and one we can pursue more prudently. States should be given the freedom to design programs that meet the unique needs of their vulnerable populations. Once given that freedom, they can truly work as laboratories of innovation, learning from one another and tailoring programs to meet the needs of their citizens. Such a re-empowerment of the states would also re-empower the poor. Instead of insurance that cannot get them a doctor's visit, they could be given meaningful choices and greater control over their own health.

We've tried the president's plan in his home state, and it's already failed. We should not let it fail the nation as well. For sick children trapped in poverty, Medicaid reform could be the difference between life and death.

Jonathan Ingram is the health care policy analyst for the Illinois Policy Institute, a nonpartisan research organization dedicated to supporting free-market principles.