"Bernie isn't a Democrat"

[Half-Century Man]

5. I don't know either.

Just trying to point out that even though third party candidate have been, so far, unsuccessful. Bernie's appeal could be wide enough, strong enough to break through that ceiling.

I've long said that we American aren't so different from the European parliamentary systems as we would like to believe. The major difference is instead of many niche parties forming coalitions to share power; We start with the left and right coalitions and fit ourselves in as best we can. We tend to gather into niche subgroups once in the overall "party".
That is why the Labor Democrats, Democratic Socialists, Progressive Democrats, Civil Rights Democrats, and Corporate Democrats, all are Democrats.
Both the pre-established left and right coalitions are currently in flux. It seems like a grassroots restructuring is about to take place. Where we might end up, I don't know.
At the moment it seems like bobbing for apples in the piranha tank.