Dismissing an appeal on a technicality, Georgia's highest court granted a victory to a Ku Klux Klan group that has been seeking for years to participate in a highway cleanup program.

The Georgia Supreme Court on Tuesday rejected the state's appeal of a lower court decision that the state had violated the KKK group's free speech rights. The Department of Transportation filed its appeal incorrectly, leaving the high court without authority to consider its merits, the opinion said.

The state attorney general's office, which represents the department, is reviewing the decision and considering its options, spokesman Nicholas Genesi said in an email.

The north Georgia KKK group applied to join the state's Adopt-A-Highway program in May 2012, hoping to pick up litter along part of Route 515 in the Appalachian Mountains. The program was started in 1989 to get volunteers to clean up sections of roads in the state. In exchange, the Department of Transportation posts a sponsorship sign along the road with the program logo and the volunteer group's name.

The state Department of Transportation, which runs the program, denied the KKK group's application, saying its program was aimed at "civic-minded organizations in good standing" and citing what it called the KKK's "long-rooted history of civil disturbance" and the "potential for social unrest."

The American Civil Liberties Union Foundation sued on behalf of the KKK group in September 2012, arguing that the state violated the group's right to free speech.

Fulton County Superior Court Judge Shawn Ellen LaGrua agreed and ruled in the group's favor in November 2014, saying the KKK's group's application was treated differently than others and that "viewpoint-based discrimination" is not allowed under the Georgia Constitution.

The state appealed, arguing that the KKK group's arguments were barred by the principle of sovereign immunity, which shields the state and its agencies from being sued in their official capacity unless the General Assembly waives that protection.

The Department of Transportation didn't have an automatic right to appeal in this case and failed to file a necessary application to appeal, leaving the high court without jurisdiction and with no choice but to dismiss the appeal, the opinion says.

Alan Begner, an attorney for the KKK group, said they are considering the ruling a victory, though he and his clients would have liked the Supreme Court to weigh in on the underlying issue of sovereign immunity in cases of constitutional challenges to government actions.

It's not entirely clear what happens next.

The Department of Transportation adopted a moratorium on allowing any new participants in the highway cleanup program shortly after it denied the KKK group's request. In her original ruling, LaGrua had dismissed the KKK group's request to order the state to allow it to participate in the program. Begner said he needs to talk to the ACLU and his clients about possible next steps.