A new voter ID law is facing its first legal challenge.

Gov. Chris Sununu signed the law last week. It requires all people registering to vote to show a passport, birth certificate or naturalization papers at the polls. Set to take effect after the November general elections, it would replace an existing system that allows people to swear they are qualified to vote by signing an affidavit, if they lack the required documents.

A new lawsuit from the New Hampshire Youth Movement, filed in federal court on Tuesday, alleges that the law violates the U.S. Constitution by making it “substantially harder—and in some cases impossible—for many New Hampshire citizens to register and vote.” They’re asking the court to permanently block the law from taking effect.

In addition to requiring all first-time voters to prove their citizenship with documentation in hand, the law also eliminates all exceptions for people who show up to vote without an identification.

The lawsuit alleges the policies will disproportionately impact younger voters and college students, “who are less likely to have ready access to the limited set of documents with which they must now prove their citizenship.” It also cites the state’s own data showing prosecutions for voter fraud, including non-citizens participating in elections, are exceedingly rare.

According to the lawsuit, more than 700 voters registered at their polling locations in 2022 using an affidavit to prove their citizenship in lieu of showing documentation, while hundreds more used affidavits to attest to their residency or identity.

The plaintiffs allege that since 2015, there has only been one prosecution for a non-citizen voting in New Hampshire.

Sununu’s office has not yet responded to a request for comment.

The lawsuit names New Hampshire Secretary of State David Scanlan as the defendant. His office has also not yet responded to a request for comment.

In June, Scanlan told lawmakers that he didn’t think the proposal was “unreasonable.”

“I don’t think that it is voter suppression or too much to ask voters to be able to give that confidence that they’re qualified to vote,” Scanlan said during a legislative hearing.

The bill was sponsored by Rep. Bob Lynn, a Republican from Windham who previously served as chief justice of the New Hampshire Supreme Court. He and other supporters said the new rules will boost confidence in New Hampshire elections and are a reasonable expansion of voting laws.