(They are not worried about it happening this year, but are extrapolating 5 years.)
This is amongst mid-westerners and west coast types. East coast liberals I talked to years ago were part of the DC or military machine, and think 100% surveillance is just a natural tool for vetting politicians: "You have to live inside DC norms since birth or will be blacklisted, even if it is just a joint in high school... Otherwise, how will the ruling class keep running things?"
This was pre-Snowden, but after the at&t leaks, and they didn't believe NSA universal surveillance was possible inside the US. Maybe their tunes have changed. Anyway, maybe that demographic is the type of 'mainstream democrats' you are talking about. Is it some other group?
(I'm talking about my social circles, not trying to stereotype entire states, regions, though the above reads that way no matter how I word it)
edit: I see you live in DC. Called it, I guess. :-(