Let me put it this way; if the GOP actually eliminated Social Security or Medicare, it would take a miracle for them to even reach 40% of the nationwide Congressional vote in 2012. If anything, Democrats should be hoping they do it, since it would destroy the Republicans electorally for a good couple of cycles. You could bring those things back & do so much more.
The only problem is that if the Republicans take the Senate, Democrats getting a super-majority in 2012 is impossible without significant defections, & we all know the Senate Demcorats can't do anything without a super-majority.