Well, I don't happen to think our system is democratic. Not by any stretch of the imagination. But they tell us it is so we'll keep playing the game. In my opinion, the whole election thing we do here in this country is bread and circuses to divert our attention away from the real issues, and to fool us into thinking we actually have any say in what goes on in this country.

But to answer your specific question, people don't have to vote for their party's candidate in the general election. When there is any restriction at all, it's in the primaries. Some states require that people vote for the party under which they are registered in primary elections (primaires choose the candidate that the parties will run in the general election). And some states do not have any such requirement. And in some states, like mine, for instance, even if the state has such a requirement, they'll still let unaffiliated people vote in the primaries as long as the state party organizations allow it. So in the 2008 primary, I was allowed to vote even though I'm not registered with either party, and even though in my state voters are required to only vote in their party's primary, because neither of the parties had any objection to my doing so.