If you're a New Hampshire voter who plans to participate in the 2020 presidential primary, you’ll want to double check your party registration this week. This Friday, Oct. 25, is the last day to make any changes to your party registration before the election.

But wait — you might be wondering — why now? And if that’s the case, you’re not alone. When NHPR asked people to share questions they have about the New Hampshire primary, many wanted to know more about the state’s unique party registration rules. (Local pollworkers have also said this is one of the most frequently misunderstood aspects of New Hampshire elections.)

This is the first in an ongoing series of explainers about the New Hampshire primary and how it works, inspired by questions we received from our audience. Check back for more in the months ahead. And if you have a question you’d like us to help answer, let us know here.

Why does your party affiliation matter for the New Hampshire presidential primary, anyway?

Right now, New Hampshire recognizes three major political affiliations: Republican, Democrat or “undeclared,” meaning that you aren’t formally aligned with either party. If you want to vote in the Democratic primary, you have to be a registered Democrat or “undeclared”; if you want to vote in the Republican primary, you have to be a registered Republican or “undeclared.” “Undeclared” voters can participate in either party’s primary. But registered Democrats can’t vote in a Republican primary, and vice versa. (More on this below.)

How can I check my party registration?

You can look it up on the Secretary of State’s website, or you can call your local clerk to ask for assistance. Every city and town is also required to have an up-to-date voter checklist posted publicly at the local clerk’s office.

How will I know if I need to pay attention to this week’s deadline?

If you are content with your current party affiliation, you can ignore the deadline. The same goes if you aren’t yet registered to vote in New Hampshire, or if you’re planning to move to a new town in the months before Primary Day.

This week’s deadline only affects party affiliation, not voter registrations in general, and people will still be able to register to vote in the months ahead. According to the state’s Election Procedure Manual, “When a voter moves from one New Hampshire town to another, the voter is treated as a new registrant for this purpose and may choose any party affiliation, regardless of the voter’s party affiliation where the voter was previously registered.”

But if you are currently registered to vote in New Hampshire, you don’t think you’ll be moving anytime soon and you want to vote in a party primary that’s different than the one you’re currently registered with, you’ll need to make that change by Friday.

What if I’m not yet registered to vote in New Hampshire, but I still want to vote in the 2020 primary?

You don’t have to worry about registering by the end of this week. This week’s cutoff only applies to people who are already registered to vote and aren’t planning to move to a new town before the primary. But it’s still probably a good idea to get that taken care of sooner rather than later — regardless of your situation. Your local pollworker will likely thank you for making their job a little easier by doing it in advance, since they tend to get busier as the election approaches.

So I checked my registration, and I might need to change it. What can I do?

You’ll have to find time to go to your local town hall sometime between now and Friday, Oct. 25, but you have until at least 7:30 p.m. that evening. By law, every town is required to hold a special session of their voter checklist supervisors from at least 7 to 7:30 p.m. on Friday to allow voters to make last-minute changes to their party status before the deadline closes. Check with your local clerk’s office for more details.

OK, but we don’t even know when the New Hampshire primary will actually be. Why do I have to pick a party now?

New Hampshire election law sets the primary party registration cutoff for the Friday preceding the date when candidates start filing to be on a primary ballot. The candidate filing period for the 2020 presidential primary begins next Wednesday, Oct. 30, so that dictated the timing of this week’s party registration deadline.

The basic idea behind restricting party registrations in this way is that a primary is a nominating contest for a specific political party, so only members of that party — or undeclared voters, as in New Hampshire and a few other states — can participate. Proponents of this approach say it protects parties’ control over their nominating contests and guards against spoiler votes from political opponents. But critics argue that this approach can be too restrictive, and voters should be allowed to vote for whomever they want regardless of their party affiliation.

Secretary of State Bill Gardner explained New Hampshire’s system this way to the Union Leader back in 2000:

New Hampshire's own voter registration process is a mix of open and closed systems, Gardner explained. "We require the person to declare a party affiliation, but then we allow the person on the way out to undeclare," he said. Technically, he said, when someone declares a party affiliation, you are agreeing to support the "principals and candidates" of that party. "But no one really asks that question," Gardner admitted. So independents are permitted to vote in either primary, by walking in on election day and asking to be switched from "undeclared" to a particular party. "Then on the way out you can say, 'I'd like to go back to being an independent; I've been a party member long enough'," Gardner said. And here in New Hampshire, he said, "A lot of people feel that way."

It’s also worth noting that it used to be harder for undeclared voters to participate in party primaries if they wanted to remain truly “undeclared.”

Until the 1990s, if you were an undeclared voter who wanted to vote in a party primary, you’d declare yourself a member of that political party by casting a ballot — at least until you had a chance to go back to town hall to update your registration after the election.

That changed in 1994, in response to complaints from voters who found that system too inconvenient or who bristled at party labels. Since then, undeclared voters in New Hampshire have been able to show up at the polls on primary day, temporarily declare allegiance with one particular party, cast a ballot, and then switch back to undeclared on their way out of the polls. In the decades since, the number of undeclared voters has ballooned in the Granite State — and they now outnumber both traditional parties.