CHICAGO (AP) — A federal judge is expected to consider a case challenging the constitutionality of Illinois’ extension of Election Day voter registration.

Attorneys will appear before Judge Samuel Der-Yeghiayan Tuesday.

Illinois piloted same-day registration in 2014 at limited locations in counties. The option was popular, particularly in Chicago. State legislators extended same-day registration the following year, requiring highly-populated areas offer it at all polls.

Republicans brought a lawsuit claiming the change is unconstitutional because there isn’t equal access, particularly for voters in less populated and Republican-leaning areas. Lawyers affiliated with the conservative-leaning Illinois Policy Institute are seeking court intervention to end poll-level registration.

Groups, including the American Civil Liberties Unions of Illinois, object. They argue a change before November would cause chaos and deny people the right to vote.