There are lots of important issues that aren't getting talking about in the 2012 campaign, but the most frustrating of them is Medicaid. This is one of the issues where the candidates are furthest apart, and they do keep discussing adjacent issues about tax and budget policy. But the Medicaid gap is so significant that, as Brian Beutler points out, Romney's Medicaid policies would likely kill off his signature achievement as governor of Massachusetts:
Unlike the ACA, the Massachusetts law has two separate markets — one for people living under 300 percent of the poverty level and thus qualify for insurance subsidies; one for people above that threshold.
The subsidized pool is called Commonwealth Care. For that market to work, Massachusetts relies on the federal government, via Medicaid, to cover half the cost of the generous subsidies it provides to lower income individuals. If Romney were to block grant Medicaid and cut its spending as dramatically as he’s signaled he would, Massachusetts would slowly lose those dollars.
This is really just the tip of the iceberg. Most of the important issues the candidates aren't talking about are subjects—from drug prohibition to climate change to patents—where the candidates simply don't have sharply contrasting agendas. But on Medicaid they really do. If Obama is re-elected, we're going to see most states vastly expand Medicaid coverage delivering health insurance to a huge swathe of lower-income America. If Romney is re-elected, we're going to see sharp cuts in federal Medicaid funding leading to huge rollbacks in coverage for disabled people, middle class nursing home patients, and the working poor.