The state Supreme Court yesterday ordered Gov. Linda Lingle to respond to a legal challenge by the state Senate over vacancies on the University of Hawai'i Board of Regents.

The Senate has sought a court order to compel Lingle to fill six vacancies on the board that opened at the end of June. Lingle has kept six regents — including Kitty Lagareta, a communications executive who is the governor's friend and former political adviser — as holdovers.

The legal challenge stems from a conflict between majority Democrats and the Republican governor over control of the 15-member board that governs the university.

Some senators also believe that Lagareta's status as a holdover undermines the Senate's advise and consent power over the governor's nominations. The Senate in May voted not to confirm Lagareta for another term.

Russell Pang, a spokesman for Lingle, said the governor's office was aware of the legal challenge but had not seen the court's order for a response. State Attorney General Mark Bennett has argued previously that he believes the six regents are lawfully serving as holdovers.

State Senate President Colleen Hanabusa, D-21st (Nanakuli, Makaha), and state Sen. Norman Sakamoto, D-15th (Waimalu, Airport, Salt Lake), chairman of the Senate Education Committee, filed the legal challenge earlier this month. The court yesterday gave Lingle 20 days to respond.

"I think it's very unusual for anyone, especially the governor, not to follow the Constitution or our state law," Sakamoto said.

Hanabusa, an attorney, said she believes it is significant the state's highest court agreed to have Lingle answer the legal challenge, known as a writ of mandamus.

"Any kind of writ like that is an extraordinary remedy and the probability of getting to the point where they are going to ask for an answer — they usually summarily dismiss it — is significant," she said.

State lawmakers placed a constitutional amendment on the ballot in 2006 asking voters whether the governor should be required to select regent nominees from a pool of candidates recommended by an advisory council. Lingle and several Republican lawmakers argued that a council would weaken the governor's discretion in appointing regents.

But voters approved the constitutional amendment and lawmakers in 2007 — over the governor's veto — created an advisory council made up of appointees of the governor, the Legislature and UH interests.

The advisory council gave Lingle a list of candidates last February for a dozen vacancies and the governor made several nominations that were confirmed by the Senate. After the Legislature adjourned, Lingle informed the board chairman that six regents — including Lagareta — would be kept as holdovers.

Bennett told Sakamoto in a letter in July that the law creating the advisory council allows the six regents to remain as holdovers until their successors are appointed and confirmed. He also cited a 1980 attorney general's opinion that found that a regent appointed for a second term but not confirmed — like Lagareta — could stay on as a holdover until another appointment is made and confirmed.

The Lingle administration has previously argued that the holdovers could stay no longer than two legislative sessions or in this case until after the 2010 session.