North Dakota's Supreme Court grilled the state Board of Higher Education's lawyer Thursday about the board's tardiness in challenging a law that requires the University of North Dakota's sports teams to carry the Fighting Sioux nickname.

State lawmakers first approved the pro-nickname law in March 2011. Yet it wasn't until last month, after the law was repealed and then revived in a referendum campaign, that the higher education board sued to block the law, Justice Daniel Crothers said.

"That harm has been there since the statute was passed almost a year ago ... Why now? Why in the face of a referral?" Crothers asked Douglas Bahr, an assistant attorney general who is representing the board, during Supreme Court oral arguments Thursday.

Secretary of State Al Jaeger scheduled a June 12 referendum on the law after nickname backers turned in more than 16,000 petition signatures demanding a ballot.

The law says UND's sports teams must be known as the Fighting Sioux and keep a separate logo that depicts the profile of an American Indian warrior.

NCAA officials have told UND that as long as the nickname and logo are kept, the Grand Forks school may not host NCAA post-season tournaments. Its teams, cheerleaders and band members may not wear them on uniforms during post-season play.