Rundown of how it tends to work on SE I would argue the following:
At the current rates of participation on meta I guess that you would need about 10 to 20 votes for something to be considered community consensus. This is always a bit of a dynamic thing and if there are opposing opinions then the one with most votes 'wins' (except in cases where one post is significantly older and the new one has gathered a substantial number of votes). For controversial things you would need relatively more votes, and anything a moderator says in his role as moderators always takes priority (though moderators have some responsibility to abide by community consensus and they still can of course share opinions without enforcing them as moderators).
Now, that's the rundown of both how I think it should work and how it works in most communities. I have seen certain communities where moderators have far more power (disregarding anything and everything that happens on meta as nothing more than users chatting with each other) and I have seen communities that are run nearly perfectly democratically (where moderators only come in when stuff goes wrong), but still, this is more or less how it tends to work I would say. Feel free to disagree of course though :) .