Democrats are ignoring (under-responding to) three key Republican arguments.:
1. Current seniors are more-or-less exempt from immediate medicare jeopardy.
2. We must act responsibly now if we care about future generations.
3. Americans of all wealth brackets must share the budgetary sacrifice.
The first argument is roughly accurate as far as it goes, and democrats are vulnerable to the charge that they are trying to scare seniors. Yes, they are trying to do just that, and they sound lame because their sound bites do not distinguish adequately between today's seniors and the millions lined up to become seniors. Those 55-60 and over are understandably concerned about the implied downsizing of their coverage, especially since the democrats are saying nothing to assuage their worries. In the face of the transparent pandering of exempting them from medicare's demise, many seniors will go along.
Related, republicans have successfully framed the second argument as if there is a distinct disjuncture--a generational gap--between that class of Americans called "seniors" and all the rest. One typical not-senior image invoked is that of a young family with school-aged children, perhaps worried about paying for college. This argument has some strength, but lots of seniors aren't worried about today's teens, 20-, and 30-somethings. Old folks in their 60s and 70s and beyond have children who may be in their 40s, 50s, and nearing or into retirement. Dems should remind seniors that their mature, adult children are at risk.
Finally, dems misconstrue the "share-the-sacrifice" argument. The argument applies to the mid-ranges of the middle class, and they don't like it one bit. Regarding the high-wealth targets of tax-increases, they would not have to make a sacrifice at all, much less share it. As Obama tried to point out, it's the difference between paying more, and sacrificing.
These are not easy arguments to refine, and there's lots of educative work to be done instead of the dems are slipping back into soundbites.