The Liberty Justice Center filed a federal lawsuit Thursday against the state of Illinois over its same-day voter registration law.
Under the law, which went into effect in 2015, Election Day voting and registration is allowed at polling places in counties with populations of at least 100,000. In smaller counties, voters can complete their Election Day registration at the offices of their local clerks.
The Liberty Justice Center argues that the law violates the 14th Amendment's Equal Protection Clause because it makes "it more difficult for people to register to vote in some areas of the state than in others."
"This scheme's arbitrary geographic discrimination appears to have been designed to benefit candidates who draw support from high-population counties at the expense of candidates who draw support from low-population counties," the lawsuit adds.
The Liberty Justice Center is based in Chicago and associated with the Illinois Policy Institute, a free-market think tank that has received donations from Republican Gov. Bruce Rauner.
Liberty Justice Center members are calling for an injunction before the November 8 election.
"Illinois' voter registration law is unconstitutional. The state cannot give some citizens better opportunities to vote than it gives to others," Liberty Justice Center senior attorney Jacob Huebert said in a statement. "If Illinois is going to have Election Day voter registration at polling places, it should be available statewide. And it should be fair."
State Sen. Don Harmon (D-Oak Park) spearheaded the voter registration legislation in his chamber. He questioned the motive behind the Liberty Justice Center's lawsuit, suggesting that it is an effort to reduce voter turnout among Democrats.
"I suspect the plaintiffs are much more interested in having same-day registration thrown out in Cook County than they are in extending it to every small county in Illinois," the lawmaker told Reuters.