If they all run an assertive campaign concurrently as they define each Republican running and the party as someone who will take away their Social Security and Medicare as Americans know it, they will win.
The Democratic party will not "take away" either. Instead, they will follow Obama's lead and diminish them until they are useless or exist solely to shovel public money to the "market". It was only the opposition to Obama's "grand bargain" from the TEA party that kept us from drastic cuts for seniors previously.
A true progressive who understands macro-econ at the federal level would be calling for the end of payroll deductions that serve no "funding" purpose and large increases in benefits from both programs. It is simply not possible to "pay for" a federal program in advance and the deductions do nothing beyond taking an ax to middle-class purchasing power.
Inflation is the only real restraint to what the federal government can "afford", and there is nothing inflationary about letting seniors live in some dignity. This nation should be ashamed of how it treats its seniors and disabled, but it would rather get mired down in economic discussion that hasn't been accurate or relative since '34 while other, brighter and more honest, nations do what is right and not subject them to the suffering that is common here for those who didn't, or couldn't, "capitalism" enough.