In theory, here’s how it works.
Starting in January, primaries are held in each state of the union. In the primaries, selected voters vote for delegates to go off to the national convention and vote for a specific candidate. You may punch the chad on your ballot for “John Kerry”, but what you’re really elected are delegates who have specifically pleged to vote for John Kerry at the convention- just as, during the November elections, you’re not actually voting for George Bush or John Kerry, but rather for electors who will go cast your state’s electoral votes for the candidate. But that’s just a technicality- there has never yet been a situation where the electors or delegates went against their constituents’ wishes in any way that mattered. (Keep in mind that delegates and electors are party officials being rewarded for service, and if they screw the party, they’re throwing away years of work and will never be allowed to do serious work for the party again.)
I say “selected” voters for this reason: in most states, primaries are “closed”, which means that registered members of the party are the only ones allowed to vote for the delegates. If you’re a Democrat voting in a primary, you get to vote for Kerry, Dean, Sharpton, etc., but can’t vote for who ends up on the Republican ticket as well. But some states have “open” primaries, which means that anyone can show up and vote for a delegate, though you still only get one vote- so you can be a registered Democrat, but still come to the polls and vote for Bush as the Republican candidate, but you don’t then also get to vote on who the Democratic nominee is.
Each state gets a number of delegates based upon weird alchemical formulae involving the number of electoral votes, how often the state has voted for that party in the past, who is actually running the convention and which candidate they want to favor, and whether Mars is in retrograde. These numbers are determined by the parties themselves, and it’s an interesting note that for a lot of the last thirty years, someone sitting on the board that determined the upcoming primary system and delegate allocation thereof ended up being the next Presidential candidate of the party (McGovern, Carter, and Dukakis, I believe, all served on those boards in the few years before they “came out of nowhere” to win the nomination).
In fact, it’s hard to say who really chooses the nominee. Because of the staggered primary system (i.e., a succession of primaries lasting several months rather than one single national primary), New Hampshire- which always has the first primary- has a massive impact on which candidates are considered “viable”. While technically Democrats in Maryland have as much of a vote as anyone, because our primary is so late in the season, the victor has usually been pre-determined by the time it gets around to us.
Yep. By registering with the party, you get the opportunity to vote in that party’s primary (again, assuming that the primary is closed, which most are.)
Debatable. I’ve seen polls stating that a lot of Nader voters are actually disaffected Republicans, which surprises me given what Nader stands for. (Even as a disaffected Republican, Kerry is much closer to anything I’d like to see in the White House than Nader, and Republicans who plan to vote for Nader haven’t read many of his policy outlines.)
Given how close the election is likely to be, any votes off of Kerry will harm him. Hell, given the margins in Florida, the International Workers of the World Party destroyed Gore’s chances with their nearly 1,000 votes.
Not that’s running. Pat Buchanan is probably the closest thing to one right now- farther to the right on social issues than Bush, a proponent of economic populism to drag away disaffected Reagan Democrats, and the only candidate still running around on a fully isolationist platform. But after he destroyed the American Party (or whatever Perot’s personal party was called) in a disastrous candidacy in 2000, he’s not in the running this year.