Despite the fact that the Dems fought Reagan and other Reps to pass Medicare, and fought to keep it strong for over 50 years in the face of Rep attacks, the Reps are trying to say that the Dems are endangering it.
Moreover, they are now trying to replace Medicare with a privatized defined benefit voucher system. This should be difficult inasmuch many people love Medicare. Please see:
http://www.truthdig.com/report/item/the_gops_mixed_medicare_message_20100217/