The announcement comes just as Magnuson readies for the highest-profile case of his short tenure. On Monday, the court will hear oral arguments in a case centered on Gov. Tim Pawlenty's 2009 solo budget cutting. The court's decision in that case could alter the state's spending and redefine the balance of power between the governor and the Legislature.

Magnuson's timing gives Pawlenty the opportunity to appoint the next chief justice before leaving office next year. The next chief justice will be the third Pawlenty has named.

Although Magnuson hasn't been at the helm of the court long, he will leave his mark on the court and on Minnesota history.

Nearly as soon as he took office, he complained publicly that Pawlenty's budget plans shortchanged the justice system.

He kept that up. Last month, Magnuson said he was "disappointed" that Pawlenty proposed a cut to judicial budgets "at a time when our base budgets are already insufficient."

By Magnuson's sixth month, he took on a task that will be part of his lasting legacy, becoming a member of the canvassing board that handled the 2008 Coleman-Franken U.S. Senate recount.

Along with the secretary of state, an associate supreme court justice, Ramsey county's chief justice and assistant chief judge, Magnuson spent weeks on the highly charged duty of determining how ballots would be counted in the race.

Sometimes with a scowl, but occasionally with a joke, Magnuson examined ballot after ballot to figure out who was ahead in the race as the nation watched.

The chief justice even took it upon himself to keep a crib sheet that marked down the board's precedents, complete with scribbles that showed how a ballot was counted, if it were marked with an X over a filled-in oval or if it were a filled-in oval over an X.

"He became the keeper of the hieroglyphics," said Secretary of State Mark Ritchie, a DFLer. During the recount, Ritchie said, he quickly came to admire Magnuson and called him "one of our extraordinary Minnesota leaders."

Eight months after Election Day and after a state Supreme Court decision in which Magnuson took no part, Al Franken was declared the winner by 312 votes.

During his tenure, the chief justice also won admirers for his care of the state's judiciary.

"He's gone everywhere," said Ramsey County Chief Justice Kathleen Gearin, who served with Magnuson on the recount board. Gearin said Magnuson would visit courts and talk not only to judges, but also to all the clerks and other staffers.

He was praised for fending off some budget cuts.

"He was able to bring together what he called all of the 'justice partners' to really present a united face and to save the court from devastating loses," Ramsey County District Judge Robert Awsumb said.

Magnuson was Pawlenty's fourth appointment to the court and helped give the court a rightward tilt. But, while the court has a more conservative bent than in years past, it rarely has been accused of being political in its decisions.

While Pawlenty reached outside the court system when he appointed Magnuson -- he came from private practice -- speculation Thursday about Pawlenty's next pick focused on those who currently don black robes.

Personal reasons

In a letter to Pawlenty, Magnuson said he was leaving "for reasons personal to me and my family." Through a court spokesman, Magnuson declined an interview request.

While in politics the term "personal reasons" often masks a hidden explanation, several of those who know him said Magnuson's rationale should be taken at face value.

"Please give deference to the fact that it's personal," advised Justice Paul H. Anderson. "Don't trip over yourself doing too much analysis."

Before joining the court in 2008, Magnuson was an attorney and shareholder at Minneapolis' Briggs and Morgan, specializing in appellate law. He previously was a partner at the Rider Bennett law firm, where Pawlenty was a young associate and, later, a partner. Magnuson took a significant pay cut to join the bench. Supreme Court justices make slightly more than $160,000 a year; a shareholder at a major law firm can earn multiples of that.

In his letter to Pawlenty, Magnuson said he would return to private practice after leaving the court.

"I'd love to have him back. He hasn't announced that yet," said Diane Bratvold, a Briggs and Morgan shareholder, whom Magnuson mentored.

Magnuson stayed at the court's helm as long as his immediate predecessor did.

Russell Anderson left after two years as chief justice at age 66 to care for his ailing wife. But Anderson sat on the high bench for a decade before he resigned. The chief justice before Anderson led the court for eight years.

Magnuson's resignation shocked legal and political communities. Observers said they didn't see it coming, and many said they'd expected Magnuson, 59, to preside over the court for years to come.

Ramsey County District Judge Margaret Marrinan said she felt "dashed" by Magnuson's resignation. Justice Paul Anderson lamented that he won't see Magnuson develop his "potential to be one our best chief justices," while court watcher and William Mitchell law school Prof. Peter Knapp said he was flabbergasted and saddened.

Pawlenty was more measured in his comments.

"Magnuson has served in this role over the past two years with great diligence, thoughtfulness and fairness. Minnesota thanks him for his service," he said in a statement.

Rachel E. Stassen-Berger • 651-292-0164 Pat Pheifer • 612-741-4992