It’s worth pointing out where the differences do lie in this Presidential campaign. And actually, it’s not necessarily on Medicare, at least as a function of spending on the program. The two campaigns have radically different views in what the program ultimately looks like, with Romney-Ryan opting for VoucherCare while Obama-Biden seek the same traditional Medicare framework with the Independent Payment Advisory Board unleashing strategies to manage the budget. But both approaches envision spending rising only at the rate of GDP + 0.5%.

A greater difference comes in their respective visions for Medicaid.

To fulfill the law’s goal of near-universal coverage, the president envisions adding as many as 17 million people to the rolls by allowing everyone with incomes up to 133 percent of the poverty level to enroll, including many childless adults. While the Supreme Court ruled in June that states could opt out of the expansion, Medicaid — and federal spending on it — is still likely to grow significantly if Mr. Obama wins a second term.

Mr. Romney and Mr. Ryan would take Medicaid in the opposite direction. They would push for the repeal of the health care law and replace the current Medicaid program with block grants, giving each state a lump sum and letting them decide eligibility and benefits. (Currently, the federal government sets minimum requirements, like covering all children under the poverty level, which some states surpass. It also provides unlimited matching funds.) The grants would grow at the rate of inflation, with adjustments for population growth. Critics say annual increases would not keep up with rising health care costs.

In pure dollar terms, the difference comes down to this: As chairman of the House Budget Committee, Mr. Ryan has proposed cutting federal spending on Medicaid by $810 billion over 10 years, largely from repealing the health care law. Mr. Obama’s expansion plan, by contrast, would cost an additional $642 billion over the same period, according to the most recent estimate from the Congressional Budget Office.

There probably isn’t another single policy item with a nearly $1.5 trillion gap in spending. And for all the conventional wisdom that you can cut Medicaid because the poor don’t vote, whereas Medicare and its focus on seniors is more of a third rail, consider that 75% of all recipients of Medicaid are elderly, disabled or children. Elderly nursing home care is quite often paid through Medicaid, and has been a lifeline for millions of families. Block grants for Medicaid could also be defined as the “Your Mother-in-Law Will Have to Move In With You Act.”

It shouldn’t be ignored that the Affordable Care Act vision for Medicaid has to now overcome this hurdle of states opting out. And the same Republican governors who want to opt out also want to block grant the program. That makes this an even more stark difference between the campaigns. Nobody’s really trying to hide their position. One side wants to expand Medicaid by 16 million; the other wants to institute a policy change that, according to the Urban Institute, will cut the rolls by 14 million to 27 million.

House Republicans don’t want to talk about their position on Medicare. Someone should ask them about Medicaid.