Does the Ku Klux Klan have a constitutional right to "adopt a highway"?

That question was at the center of a high-profile battle Monday before the Georgia Supreme Court, where the Klan is challenging the state's refusal to let it participate in the popular Adopt-A-Highway program.

The hate group, with the American Civil Liberties Union by its side, is casting its bid as a free speech issue.

“The government cannot be a censor of free speech,” Alan Berger, an attorney for the International Keystone Knights of the Ku Klux Klan, said.

But the Georgia Department of Transportation has resisted the KKK's efforts ever since 2012 to join the program.

For its part, GDOT maintains it should be allowed to exclude certain groups from the program -- and stands by its claim that the KKK’s “long rooted history of civil disturbance” would “cause a significant public concern.”

Monday’s arguments centered around Georgia's claim of so-called sovereign immunity – a legal doctrine that shields the state from civil suit or criminal prosecution. The state had appealed a lower court decision by Judge Shawn LaGrua, who ruled Georgia was not protected against the KKK suit because the group claimed the discrimination involved a violation of its constitutional rights.

“The state denied the application, not because of safety hazard or some other compelling government interest, but because the state disagrees with what the KKK represents,” Maya Dillard Smith, executive director of the ACLU of Georgia, told FoxNews.com. “It is precisely this kind of government action the Constitution prohibits.”

While Smith admits that many people who hear about the case have a “visceral reaction” to it, she warns its outcome could have a dangerous ripple effect.

“What may seem as chipping away only at the KKK’s free speech right, will, in fact, open Pandora’s box and create legal precedent that justifies curtailing the free speech rights of religious evangelicals, abortion protestors and even Black Lives Matter supporters and opponents,” she said.

A judgment is not expected for a couple of months, Berger told FoxNews.com following Monday's oral arguments. In the meantime, GDOT has suspended Adopt-a-Highway applications.

This isn’t the first time a state has gone rounds with the white supremacist group.

In 1994, Missouri tried to block the Knights of the Ku Klux Klan from participating in its Adopt-A-Highway program.

The group -- which excludes anyone who is black, Jewish, Mexican or Asian -- had requested a half-mile section of road on Interstate 55, one of the routes that had been used to bus black students to school as part of desegregation efforts near St. Louis.

The state denied the KKK’s request.

In that case, lawyers for the state unsuccessfully argued that it had a right to control its own speech and that allowing the Klan to participate would violate the 1964 Civil Rights Act’s ban on racial discrimination in federally funded programs.

The U.S. Supreme Court refused to hear the case, thereby forcing the state to allow the group to take part in its “Adopt-A-Highway” program. However, the state later kicked the group out, saying it failed to do its job and pick up the litter on its adopted stretch of highway.

In 2009, the National Socialist movement, a neo-Nazi group, tried to adopt another stretch of road in Missouri. In response, officials renamed the part of the highway after Rabbi Abraham Joshua Heschel, a man had who fled Nazi Germany and later became a popular civil rights advocate.

In 2005, two green signs popped up on a rural road in Oregon that seemed to suggest the American Nazi Party was participating in that state’s Adopt-A-Highway program. Complaints poured in after the signs were featured on a local newscast. One sign was even vandalized.

In an email to The Spokesman-Review, the group’s leader Rocky Suhayda denied involvement in the program, saying the group “would never pick up garbage along a highway in this toilet-bowl of a country.”