A Question for Paul Ryan

Earlier this morning I wrote a post about the differences between Paul Ryan's 2012 Medicare plan and Paul Ryan's 2013 Medicare plan. My point was simple: the 2013 plan is quite different from the 2012 plan, and if we're going to attack his plan, we should be attacking the current one.

So here's the main point of attack: Ryan's 2013 plan relies on competitive bidding to lower costs. Healthcare providers all bid for Medicare contracts, and seniors get a voucher equal to the second lowest bid. That way, there are always at least two plans they can buy without having to fork out any money beyond the value of the voucher.

But Ryan also includes a "fallback" growth cap. The overall cost of Medicare won't be allowed to rise faster than GDP + 0.5%.

So here's the question reporters should be asking Ryan: What happens if all the bidders submit bids that are over the growth cap? Who pays the difference? Seniors?

If not seniors, then who? You can't just arbitrarily force everyone to lower their bids. Nor can you lower payments to providers for specific services, since you're just soliciting bids for insurance coverage, not paying providers directly for services. So what happens?