This has to have created one of the best buying opportunities ever. No way the government would dare let the guarantees on agencies disappear. We've had Charles Schumer say they'll be supported, and John McCain. The risk is tiny.
Well technically GNR is the only one guaranteed by the gov (ie bail out no matter what), but FHR, FNR are implied to be backed if the gov so chooses...ie they don't have to (sponsored). The result of a failure imo would be too great and therefore I believe there will be some plan to save the bonds as well as the entities, but as always, at the expense of the common holder.