That's because if you want your party to win you nominate a moderate.
I think Assange meant "allowed by the powers that be", rather than "allowed by the voters". Which I think is a bunch of paranoid drivel, but then, my opinion of Assange was never very high...
It's just sad that right leaning moderates don't have a home anymore.
apparently if you promise everything and you run against a boring moderate you can win.
D'uh. The only reason Trump is there is to make Clinton look good by comparison.