Arkansas has always had open primaries since primaries first began early in the 20th century. However, on June 8, 2024, the state Republican convention voted to close Republican primaries, so that only registered Republicans can vote. However, the state chair and the state executive committee of the Republican Party then took the position that the convention action is void, because proper notice hadn’t been given in advance of the convention about that vote.
On August 26, some Republican state convention delegates sued the party’s State Chair and State Executive Committee in federal court, to force those officers to accept the decision of the state convention. The lawsuit also sues the Secretary of State. Lancaster v Thurston, e.d., 2:24cv-161.
Here is the Complaint, which attaches the party rules to establish that the state convention is the ultimate authority in party governance.