RALEIGH, N.C. (AP) — A portion of a 2019 North Carolina law designed to toughen mail-in absentee ballot rules following a fraud investigation in a congressional race went too far and is unconstitutional, a lawsuit filed on Wednesday contends.

Lawyers for Advance Carolina, a group that works in part to get African Americans out to vote in the state, said the new limits on who can help someone fill out requests to obtain a ballot violate state constitutional protections. The group wants enforcement blocked of what it calls the new “application organizing ban.”

The ban not only denies “voters valuable assistance in obtaining absentee ballots to facilitate their political participation, but it also infringes on the core political speech and associational activities of organizations and citizens working to increase voter turnout,” attorney Burton Craige wrote in the lawsuit filed in Wake County Superior Court.

The law was approved by the state House and Senate in October with only one “no” vote and signed by Democratic Gov. Roy Cooper.

Supporters of the legislation say it attempted to combat illegal ballot "harvesting," which occurred in the 9th Congressional District campaign in 2018, according to evidence collected in a State Board of Elections probe. The investigation led to a new 9th District election last September.

The traditional absentee ballot process remained largely the same in the new law: a registered voter fills out a ballot request form that gets sent to the elections board in their home county. The county board then sends an absentee "application" and a clean ballot to the voter, who then fills out both.

While the measure increased criminal penalties for people who attempt to sell or destroy others' completed absentee ballots, Advance Carolina said it made no sense to further restrict who could help fill out a ballot request to only the voter or a close relative. The collection of completed or partially completed ballots was the key element in the absentee ballot probe in the 9th District, focused on a Republican operative in Bladen County.

An outside individual had been previously able to help with the ballot request form, which allowed political groups to implement get-out-the-vote efforts. Now, the lawsuit says, there are now “greater restrictions on completing absentee ballot applications than it does for filling out and submitting absentee ballots.” This amounts to an unconstitutional burden on the right to vote, according to Advance Carolina.

The state and the State Board of Elections are among the defendants in the case. Joseph Kyzer, a spokesman for House Speaker Tim Moore, told WRAL-TV the bipartisan law doesn't prevent any organization from encouraging absentee voting and will be defended by legislators.

The plaintiffs' lawyers also include several from a Washington, D.C., law firm that helped represent Democrat Dan McCready, who ran unsuccessfully for the 9th District seat in 2018 and 2019. He and his campaign weren't accused of any wrongdoing.