On the other hand- and there definitely is an "on the other hand" here - the slowed growth that the Ryan plan at least ostensibly makes explicit are baked into the math of inevitable retrenchment in the ate of healthcare expenditure growth compared to GDP. The Obama approach, while clearly within "Medicare as we know it," involve a similarly reduced growth rate by different means.
So it admittedly isn't fair to tag the Ryan plan with the fact that the rate of healthcare expenditure growth must slow.
By the way, each side rightly points out that the other can't really "show us the money" re. The actual credibility of its claim that the rate of healthcare expenditure growth will slow. For the Obama side, it goes to the success of the apparatus to slow growth, raising issues of both how it works in the field and of political resolve. For the Ryan plan, it's straight political resolve, as in: Why should we believe future Congresses will be willing to hold the line when Ryan himself won't do so in the short-term budget?
Medicaid is another matter. The Republicans appear quite willing to shred this program, although it may turn out to have widespread political support extending to their own voters.
- I am giving a talk at the U of Illinois Law School next March, at an endowed lecture on retirement issues, where I will attempt to address the underlying philosophical differences in terms of political economy and inter- (as well as intra-) generational risk-sharing, with Paul Samuelson's famous model of Social Security playing a key role. I will be aiming for higher ground than current political spats. But clearly I will have to write it in lieu of whatever happens in this year's election.