Last week, five Lafayette County residents sued the state of Mississippi to challenge the law, which requires political committees or groups to register if they raise or spend more than $200 a year toward their cause.
The group asked the U.S. District Court to stop enforcement of that law, claiming it limited their fundamental free-speech and association rights.
They sought to campaign for passage of Initiative 31, which aims to change the state's eminent domain law.
Judge Sharion Aycock will hear their arguments and the state's response starting at 1:30 p.m. in the U.S. Courthouse in Aberdeen.