CONCORD, N.H. — A New Hampshire law that will make residency a condition of voting in the state unconstitutionally restricts students' right to vote, the American Civil Liberties Union said Wednesday in a lawsuit.

Under current law, New Hampshire is the only state that doesn't require residency. The federal lawsuit filed against Secretary of State William Gardner and Attorney General Gordon MacDonald was brought on behalf of two Dartmouth College students. They say the law, which takes effect July 1, burdens their right to vote by requiring new voters to shift their home state driver's licenses and registrations to New Hampshire.

"Under this law, I have to pay to change my California license to be a New Hampshire one," one of the students, Maggie Flaherty, said in a statement. "If I vote and don't change my license within 60 days, I could even be charged with a misdemeanor offense with up to one year in jail.

"Make no mistake — this is meant to deter young people from participating in our elections, and students are an important voting bloc here," Flaherty said of the first-in-the-nation presidential primary state.

Gardner said he sees the issue as "everyone who votes ought to vote under the same standards. There should not be different classes of voters."

The current law allows college students and others to vote who consider the state their "domicile," that is, counting the state as their place of residence "more than any other place." That doesn't carry the requirements of "residency," which has people get driver's licenses and vehicle registrations if they are staying "for the indefinite future," language that's no longer in the new law.

Republican Gov. Chris Sununu initially expressed concerns about the constitutionality of the law, which was passed by the then-Republican controlled Legislature last year. He requested an advisory opinion from the state Supreme Court. The court said that eliminating the distinction between "residency" and "domicile" for voting purposes would be constitutional, siding with Republicans who argued that out-of-state college students who vote in New Hampshire should be subject to the same requirements as everyone else.

Sununu, who signed the bill into law in July, had said it "restores equality and fairness to our elections." Democrats argued it amounts to a poll tax and would deter students from voting. In its ruling, the court said that even if removing the distinction between residency and domicile creates a burden on them, the state has a compelling reason for making the change.

"We have received the complaint filed today," said Senior Assistant Attorney General Anthony Galdieri, chief of civil litigation. "It is the Attorney General's duty to vigorously defend the laws of our state and our office will do so in this case."

Deputy Secretary of State David Scanlan had spoken in favor of the bill last year. He emphasized that neighboring states require those who vote in their states to become residents, subject to motor vehicle and other laws.

"Just being domiciled here and not being a resident is an absurd result," he said.

A separate lawsuit brought by the New Hampshire Democratic Party and the League of Women Voters challenges a 2017 law requiring additional documentation from voters who register within 30 days of an election. Supporters argue it will increase trust in elections by requiring people to prove they live where they vote, but opponents argue it is confusing, unnecessary and intimidating.