That’s what’s referred to as an “open primary”. When a state has an open primary, some people will cross the aisle to vote for the guy in the other party who promises to drown all the cute kittens and puppies and make Satanism the state religion in the hope of setting up an easy victory in the general election.
It should be clarified for non-U.S. people reading this thread that registering with a party does not in any way limit who you can vote for in the election. For example: Say I register Republican and vote for my favorite candidate in the election. He loses, and they put up someone I don’t like. In the general election, I’m free to vote Democrat (or Libertarian, or Green, or whatever).
It’s very common for people who affiliate themselves with parties other than the “big two” to register ® or (D) anyway. That way, you can select a “next best choice” from one of the big parties, because your vote for your candidate is (unfortunately) mostly symbolic.
Registered “independents” or “no preference”, while giving up the opportunity to pretend we’re helping to choose who will run, still can vote in the actual elections.
To vote Democrat, you don’t need to be a “card carrying”, dues-paying party member. Just indicating a party preference when registering makes it enough so you can vote for that party’s primary candidates but can’t for the other party.
But why shouldn’t you have a right to help select from a field of candidates for one office and another field for another? Again, local issues don’t necessarily have the same issues as national ones; local issues aren’t always divided along party lines, and local issues don’t always have a formal, stated party position – it’s often up to the individual candidates.
I think the original reason for disallowing crossing party lines was to avoid a Democrat voting for the weakest Republican to influence the subsequent general election. Dunno if that has ever happened, but I guess it could.
No, the original reason for disallowing crossing party lines was exactly as I said: to reward party membership. Open primaries are a later innovation.
And while it may be true that some local issues don’t split on party lines, in my experience the great majority of local elections, down to village level around here, are more definitely partisan affairs.
It doesn’t matter though. Either selecting candidates are a party function or they are not. I don’t think you’ve given any good reason for allowing people to pick whatever party they want to influence rather than limiting party representation to party members.
Yes, it has happened.
Dan Savage has written that it’s his policy to register Republican and vote for the biggest schmuck during the Presidential primary.
For a while California had an Open Primary system, which meant that (eg) Democrats could vote in the Republican primary. I know of at least one person who implemented the Dan Savage strategy, and voted for the most persuasive putz in the opposing party. California’s current modified closed primary system is described here.
Registering to vote automatically annuls previous registrations, if any.
Right now I’m moving to a private message 
States and territories with open primaries (any voter may vote in the primary of either major party, but not both): Alabama, Arkansas, Idaho, Illinois, Indiana, Michigan, Mississippi, Missouri, Montana, Puerto Rico, South Carolina, Texas, Tennessee, Vermont, Virginia, Wisconsin.
States and territories with open caucuses (any voter may vote in the primary of either major party, but not both): American Somoa, Minnesota, North Dakota, Virgin Islands.
States with modified primaries (independents may vote in the primary of either major party): Georgia, Maryland, Massachusetts, Nebraska, New Hampshire, New Jersey, North Carolina, Ohio, Rhode Island, West Virginia.
State with modified caucus (independents may vote in the caucus of either major party): Utah
If you are registered to a particular party, is that information private or public? Can anyone look up your party affiliation on the state register?
I’m not sure if it is available online, but locally, the following is available as a public record to anyone who wants to pay a minimal fee to obtain digital records:[ul][li]Name and address of registrant[]Party affiliation, if specified[]Which elections voted in, for the last 10 elections[/ul]The last item is merely a “checkbox” – did they vote in election X or not (including primaries and special elections); it doesn’t tell who or what they voted for, of course.[/li]
Campaigners regularly use this data to target voters. Why make a personal visit to someone who votes regularly and is likely to vote the straight party ticket? Or perhaps concentrating on getting out the vote from those who vote infrequently. A friend of mine once got pissed when I told her I never voted (just kidding), and she found out I never missed an election.
Because some offices have little or nothing to do with party goals or platforms, yet laws may require a stated affiliation. AFAIK, the Democratic Party platform has no guidelines useful for picking our town’s chairman, or if it does, no one knows what that is. I honestly don’t know what our town chairman’s political affiliation or personal political beliefs are and I don’t care. They simply don’t relate to local needs. Candidates to local offices (around here, YMMV) could even switch parties and I doubt if it would affect the votes they get much. I suspect some may have even chosen the party to run under to avoid elimination in a primary (if candidates A & B are both Democrats and no Republicans are running, either A or B will be eliminated in a primary, but if one switches sides, both will prevail thru the primary and be on the general ballot).
You’re right in that the overall concept needs to be defined. Is a primary’s purpose to narrow choices by party or merely to narrow the overall field? I argue that the former is incompatible with some local politics.
[QUOTE=Musicat]
I’m not sure if it is available online, but locally, the following is available as a public record to anyone who wants to pay a minimal fee to obtain digital records:[ul][li]Name and address of registrant[]Party affiliation, if specified[]Which elections voted in, for the last 10 elections[/ul]The last item is merely a “checkbox” – did they vote in election X or not (including primaries and special elections); it doesn’t tell who or what they voted for, of course.[/li][/QUOTE]
And that doesn’t bother anyone? If I were registered to the Let’s Kill Puppies party, I’m not sure I would want people to know about it. I realise that you don’t have to specify an affiliation, but then you can’t vote in primaries, right? (although I realise that it varies from state to state). Also, whether I voted in the last ten elections or not is nobody else’s business than mine.
Not in Wisconsin.
In addition to the open caucus, Minnesota also has an open primary (for any races where a candidate does not abide by the endorsement). In 2006, it affected the DFL (Democratic-Farmer-Labor) race to be the Attorney General candidate. The DFL-endorsed candidate lost to another candidate, who eventually won the office. That specific race was kind of a clusterf**k, though, and isn’t a great example of how the system usually works.
ETA: I forgot to write the think I meant to write in the first place. In MN’s open primary, every voter gets the same ballot (at least we do, out here in the sticks). It has all the contested primary races for all the parties. You can only vote for one party (so, you can’t vote on who is going to be the GOP candidate for State Auditor, and then turn around and vote for who is going to be the DFL candidate for Attorney General). If you make a mistake, the scantron machine you put your paper ballot into tells you, and you get to fix it.
In my state (MA) you can ask for whatever primary ballot you want (therefore registering for that party) then after voting, immediately change your registration back to Independent.
But the main point is that party registration is only meaningful when you are voting in a primary, and can be changed so quickly, that it caries no real significance. People aren’t worried about people knowing what party they registered for because party registration means so little.
We should note that party registration also has the significance that it puts you on that party’s rolls for solicitation and party propaganda. Your party registration may net you a bunch of junk mail and unsolicited phone calls asking for donations or reminding you to vote, and vote their way as a good little loyal party supporter. Note that the “do not call” list specifically exempts political organizations along with charities, surveys and and “prior business relationship”. As someone who is registered Democrat solely in order to vote in primaries, I don’t object too much to the junk mail telling me how wonderful the Democratic candidates are, but recorded phone messages of Bill Clinton I can do without. The last time I got a LIVE phone call from the Democratic party I told them point blank “Look, I’m registered with a party ONLY because this state doesn’t have open primaries.”. It DID shut them up, and I haven’t heard from them for a while. Maybe they’ve got some sort of “not really one of us” list. I hope.
I’m a former election official. It’s a wonderful way to expose hypocrites who run for public office when they haven’t voted in the last 10 elections — especially when they point blank lie and say they vote regularly.
BTW, the wiki article on US presidential nominating conventions includes some historical background on the emergence of the primary election:
As noted there, the last major party convention that was in any serious doubt was the 1976 Republican Convention, when Reagan challenged incumbent Gerald Ford.
Previously, the stretched out primary season built up a consensus as caucuses and primaries were held in various states. I can just see all these early primaries resulting in delegates still scattered all over the field by the time most primaries have already happened, with one of two results:
1 - some small state which still has a late primary will effectively choose the candidate.
2 - nobody has a majority, and we wind up with a “brokered” major party convention for the first time in recent history.
Just want to add one overall item that might help non-Americans understand how our elections work. We never, ever, ever have nationally run elections in the US. Even when we elect our national politicians (President, Senate, House), those elections are administered by each individual state. They usually occur on the same day (the regularly scheduled ones are mandated by federal law to do so), but each state runs them as if they were a separate event. And every state ballot looks different from every other state ballot, partly because most states have state-specific issues on their ballots, too. Hell, you’d probably find that in most cases the ballots don’t all look the same within a given state (because local issues get lumped in their, too).
It may sound confusing, and it may seem crazy but we make it work. Well, at least most of the time. 
As far as voter registration information:
Imagine for a moment that I am running for Township Commission. Suppose you need to get 100 petition signatures of registered voters in the Kill Puppies party. Without the information, you could start walking from door to door and asking every single person to sign the petition. Of course, if you hand in 1,000 signatures, 99 of which are from the Kill Puppies Party members, I guess you are fucked. You’re off the ballot. With voter registration info, you can go to the doors of registered Puppy Kilers and get signatures more efficiently.
As far as voter history:
Turnout in a municipal primary election out here is less than 25%. So I guess you could again, go to every single house and campaign. Of course, 75% of the voters that I meet have no intention of showing up, no matter how much you ask. So that’s a lot of valuable time down the crapper. On the other hand, if you go to the houses of voters who have a good voter history, you can spend a lot more time getting the message out to folks who will care enough to vote.
That probably sounds like bullshit to you. But try it sometime.