Democrats are counting on being able to paint Paul Ryan as a crazed Tea Party radical danger to Medicare. Once they get past the simple loud chanting of the slogan "Ryan will destroy Medicare," from time to time the left wingers have to try to provide the proof that their mindless chant has some truth to it.
Ground Zero of that debate is the truth that the Ryan plan would allow people under 55 (at whatever year the plan gets implemented) to have a choice of options regarding Medicare that would not be voucher-like, but would provide customizability of personal health insurance under "premium enhancement" existing provisos.
The Ryan plan, in fact, is almost exactly like what federal government employees already have--an ability to opt out of certain provisions of Medicare in order to optimize other concerns.
Democrat rhetoric basically obliterates all those fine talking points with a shotgun approach of shriek and repeat.
Will the American people swallow whole the tried and true propaganda technique of repeating a falsehood loudly enough and often enough that, like an urban myth, the Big Lie takes on a type of credibility simply because of cultural inertia?