>> Maybe the fact that he's a United States Senator, rather than governor of Vermont. <<
I understand, but he worked his way up through the political ranks in Vermont so I would assume he has a lot of influence in state politics. Since his constituents support his policies, I think socialism would be easy to implement in a small state.
My point is that leftists must always do things on a grand scale. For example, single payer health care was a failure in Vermont (see below) but the only thing leftists learned is they need a bigger pocket to pick.
BTW -
In short, if a liberal state electing a Socialist (US Senator Bernie Sanders) to Congress can't or won't put a single payer system into place, then who will?
Costs derail Vermont's dream of a single-payer health plan