Why can't I register with multiple political parties (at the same time)?

I've searched the web, read forums, sent emails, made phone calls, and I cannot find a satisfactory answer to this question. The response I usually get is "Why would you want to?". I feel that my personal reasons are unimportant. Unless there is a good reason to restrict it, why restrict it?

I don't fully identify with any established party. For example, I see good and bad things about the ideologies of the Democratic, Republican and Libertarian parties (and other parties, but these are the main ones I'm interested in), but don't feel fully "at one" with any of them.

When the Democratic primaries roll around, I'd like to be able to have a say in who that party ends up nominating. Same with Republican primaries. Same with any other primaries (if they have them). Some say this violates the "one person, one vote" rule. I say it does not. I still only have one vote, but it's per party that I'm registered with.

I know it's possible in some states to vote "cross-party" but as far as I know (again I'm not the most politically-knowledgeable person) once you've cast your vote in one party's primary, you can't vote in another's primary. Or can you? Regardless, where I live (Arizona) I know that's not allowed.

I also know that I could (if the timing is right) register with party A, vote in their primary, then register with party B, vote in their primary, etc. But this is ridiculous. And if the timing isn't right (primaries are held too close together) not possible.

I realize I probably have a lot of misconceptions here, but that's why I'm posting this question.

  • 2
    It's funny. My first reaction was "why would you want to?" Nov 27, 2014 at 15:38
  • One vote per party you're registered with is more than one man, one vote. If you are registered with three parties, it's one man, three votes, which is more than a person registered with fewer parties.
    – Publius
    Nov 27, 2014 at 19:27
  • 5
    But isn't the purpose of a party's primary election for the party to decide who to nominate for the general election? In the non-political world, I could be a member of multiple similar (for example) clubs. Say each club wants to nominate a representative to run in some inter-club race. As a member of club "A", I would vote for the person who I felt best represented that club. Then as a member of club "B", I would vote for the person who I felt best represented club "B", and so on. Aren't the primaries similar to this? They are specific to each party? Unrelated to the general election?
    – paulv
    Nov 27, 2014 at 19:57
  • Read here politics.stackexchange.com/questions/93/…
    – Kennah
    Nov 27, 2014 at 21:42
  • 1
    @paulv, could you provide us the source that state that you cannot register in multiple political parties? Dec 4, 2014 at 16:47

4 Answers 4


Parties control the rules for their own primary elections, subject to state law.

In your particular case, it doesn't matter. Arizona allows people without a party to vote, so just don't declare one on your registration.

Party Affiliation: No party registration required for primary voting

You are going to have 50 different answers if you want a more general answer. Voting laws are controlled by the states, except in the few cases they conflict with federal law. Open Primaries and Closed Primaries have both had constitutional challenges with differing results.

  • 1
    Does that mean that in Arizona, since I am not registered with any party, I can vote in party A's primary and then later party B's primary? If not, then basically whoever I vote for first becomes my de facto party affiliation, which means I basically have to choose one party anyway.
    – paulv
    Nov 27, 2014 at 20:14
  • 4
    @paulv - You can choose whose ballot to use, but you still only get one party's ballot. (§16-467).
    – Bobson
    Dec 5, 2014 at 16:44

You post a very interesting question here, without going into too much detail. Its not legally wrong to be a member of multiple political parties (think of political parties as membership organisations) unless within the rules, regulations and code of conduct of said parties there is a clause preventing you from joining other parties (Some political parties do have this).

  • 2
    See that makes sense to me. I don't even know why voter registration even asks for a party. Seems to me that registering to vote is a separate process from becoming a member of any political party. I guess I'm saying I see parties as independent "groups" and as long as I abide by the rules within each group, I don't see a problem.
    – paulv
    Nov 27, 2014 at 20:01
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    @paulv Voter registration asks for a party, in part, to facilitate a government run political primary process that was historically a closed primary process even though it has been reformed in some states, and in part, to facilitate the redistricting process and to make it easier for political parties to identify and reach out to prospective supporters.
    – ohwilleke
    Jul 24, 2017 at 0:07
  • @ohwilleke so you should indicate your affiliation with the wrong party to make them waste time Nov 1, 2021 at 17:41

Every state and political party has their own rules for registration and primary voting. As user1873 pointed out there are some states that allow you to vote without being registered in primaries, but I believe this is the minority of cases.

There are no laws restricting registration and how it is handled, so the political parties are free to set their own rules for registration. if they choose to say you can't register with them if you have registered with another party well in absence of any law preventing that they are free to do it. Likewise they are free to have closed primaries where you cannot vote if you are not registered because no law has been written forbidding it.

So the question really is why, in the majority of cases, do political parties prefer closed primaries as opposed to the open primaries of Arozona and a few other states? I'm not an insider with the political parties and so can't say for certain; however, I suspect it's a combination of two key concerns that inspires closed primaries.

Encouraging loyalty to the party.

By forcing a voter to pick your political party to be allowed to vote in your primaries you can ensure they focus their attention more on your party then on the other party. So, for example, if they vote for Candidate A in your primary after thoroughly considering all the various candidates your party has they are likely well informed about Candidate A's policies and beliefs. By contrast they may know comparatively less about the other political parties Candidate B, because there was less reason to research that candidate since they couldn't vote in the other parties primaries. That means you are starting your race for president with a voter that is more informed about your candidate then your opponent, which may ultimately sway the voter towards voting for the one they are more familiar with.

There are many similar arguments for party loyalty. The more that a voter sticks to one party they more they tend to fall into group think, the more frequently the vote for that party etc. Making someone feel 'part' of a party, by getting them officially registered for it and letting them in on the super secret primary voting, helps to make them feel more a part, and loyal, to your party, which in turn boosts the odds they will continue to vote for it. You don't get this sort of loyalty from an independent voting in both parties primaries.

Prevent sabotage votes.

If anyone can vote in your primary then in theory people who identify with the other party could vote in your primaries in an attempt to sabotage it by voting for the worst possible candidate. In reality I believe it's unlikely this would become a problem for a party. A few sabotage votes aren't going to sway an election by themselves so sabotage would only work if a political party went out of their way to organize a large scale sabotage campaign to encourage all their voters to make sabotage votes, and such an action is unlikely to end up helping the party that organized it once the backlash and negative publicity sinks in. Having said that there are some who are concerned about this threat, rather or not it's realistic, and to them closed primaries which theoretically prevent it are considered preferable to having a potential vulnerability.

I have to play devils advocate, I'm pro devil you know...

Now for the sake of playing devil's advocate I should point out the biggest downside to closed primaries, and the reason some states don't do that. This issue basically comes down to an inability to appeal to independent voters, which is imperative if you want to win presidency. The best way for a politician to win closed primaries is to be the most extreme support of their parties political views. However, someone who is extremely left or extremely right may not appeal to independent voters who are more likely to prefer a more moderate candidate. By allowing independents to vote in your primaries you increase the odds that a candidate will be picked that appeals to independents by allowing the independents to have a say in who your candidate will be.

Since Democrat's already have a partial protection against the tendency for primaries to lean towards the more extreme, and potentially less appealing to moderates, candidates in the form of super delegates arguable they would arguably suffer a little less from closed primaries then Republicans who don't have such protections, though I have not personally seen any study or analysis on this topic.

  1. Most party rules insert a clause that all electors in the primary will support the candidate in the general election. This is to prevent sour grapes if "your candidate" doesn't win.

    Obviously it isn't enforceable, but it is a gentleman's agreement sort of thing. If you are supporting candidates in both parties, you are ipso facto going to be breaking your "word" to one of them.

    I certainly wouldn't want you voting for a candidate knowing you won't hold to your word.

  2. Finally, imagine if several people did this. Want to know what they'd do? Pick the candidate they want in one party, and choose the weakest candidate in the other. That is usually considered bad behavior on either side. These may not be "laws" but they are common courtesy. Democracy works best when each side is allowed to put its best foot forward. Anything less is just dirty pool.

Regardless of whether or not you "can," you really shouldn't.

  • My reasoning is that I'd like to support the best candidate (to my eyes anyway) within each party. I wouldn't vote for the weakest in one and the strongest in my "preferred" party. I don't vote based on party. I vote based on the strengths of the candidate. I get what you are saying, I just find that line of thinking based more on fear than reason. A strong candidate is a strong candidate. A weak one is a weak one.
    – paulv
    Nov 27, 2014 at 20:09
  • 2
    You may have good motives, but how do the parties differentiate between you and those with bad motives? Nov 28, 2014 at 4:39
  • -1: look at your answer in meta, and compare the last sentences of both. Nov 30, 2014 at 13:37
  • 1
    @J.C.Leitão Answers are different than questions. This is the standard response you'd get if you were to ask any party's committee chair. I know. I've been a delegate to my party's caucus before, and this was explicitly announced. I'm okay leaving a -2 answer out there, because I'm right :) Dec 4, 2014 at 16:16
  • 1
    I am not aware of any state political party that has a requirement that rank and file members vote a party-line slate in the general election and the general election secret ballot rules are specifically designed to make it impossible to impose such a requirement.
    – ohwilleke
    Jul 24, 2017 at 0:09

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