The US presidential primaries are in the news on a regular basis these days and every time they're mentioned I end up with the same question. When there's a democratic primary who gets to vote? Party members only? Or the entire state?

If it's party members only, do all Americans belong to a political party, or is this just a small percentage?
If it's the population of the entire state: how do you make sure that the candidate who wins is the one that is best for the democratic cause and not the one who's going to put up the least resistance to the republican candidate?

Leau78, only registered Democrat voters get to vote in primary elections where a Democrat candidate will be selected. They are voting for the candidate who will represent them in the general election on November 4.
All Americans do not belong to a particular party nor do they have to to vote in the general election. For example, I am an independent voter, not tied to any candidate but I do vote at the general election.
We have a lot more political parties than just the Republicans and Democrats, but these two parties have the greatest chance of winning an election.
During the last Presidential election, the Green Party, the Communist party, and others that I can't think of at the moment got on the ballot in some states. The requirements to get on a ballot vary state by state but usually require a small percentage of registered voters signing petitions to get their candidate on the ballot.
The squabble as to who is best to represent the Democratic party in the general election is the process going on right now with primary elections in several states. The candidate who garners the most primary election votes across the country will be the candidate in November.
Clear as mud, right?

Always makes you wonder who invented the rules, right?
I know there are more parties than just the democrats and the republicans, just left them out for the clarity of my question. The US elections are always well covered on Dutch television and they do explain the rules for the presidential elections, but somehow they just assume everyone knows how it's done in the primaries (or maybe they assume no one cares ).

So, when are you a registered democrat voter? If you're a member of the party? (I just thought of the fact that being a member of a party might mean something different in the US than it does over here). I guess you can't be a registered voter for two parties, right? Please enlighten me.

By the way, are the republicans going to have primaries as well, or is George W. already set as their candidate because he's the president?

Take a look at this site for more in-depth review of the primary voting process:
http://www.gwu.edu/~action/chrnothp.html

Of course all the rules are different if you live in Florida!

cheers
Maynooth

Thanks again, fjohn! I read the site you mentioned, followed some links and ended up reading the party rules of the Republicans. Definitely not the kind of English we're being taught in school! But I think I get it now, at least to some extent. Won't get confused if the primaries are on the news again. Thanks!