President Barack Obama is promising to lay out his long-awaited ideas on how to restrain Medicare and Medicaid spending this week — just in time to take the spotlight away from Paul Ryan. But he'll have to do it in a way that doesn't provoke a Democratic revolt or give the Republicans an easy target. And right now, there aren't a lot of Democratic ideas on either Medicare or Medicaid that Obama can just pull off the shelf, dust off and use.