Obama and Romney have fundamentally different approaches to Medicare and they deserve attention. Romney, for example, wants to increase the eligibility age to 67 and convert Medicare into a voucher system that relies primarily on competition between private firms to rein in costs. That's a big change. At the same time, the actual differences in what the two candidates would spend on Medicare is fairly modest. This is more a fight over means than ends.

The same can't be said for Medicaid. Romney wants radical changes here too, promising to "block grant" Medicaid if he's elected. This means the program would be turned over entirely to the states. The federal government would continue to provide a share of funding, but that funding would go straight into state coffers, and states could decide how to spend it. So the question is: Once released from federal regulations, what would states do with their Medicaid money?

Some states would probably try some genuinely interesting experiments, though it's unlikely we'll ever discover any magic bullets for reining in health care costs on a state level. But lots of states, especially poor states in the South, don't have much interest in experimenting. They just want to slash eligibility for Medicaid.