When the state Department of Mental Health sells its historic Bull Street property in Columbia, it will receive at least $7.5 million more than the agency originally expected. That boon can be credited largely to the painstaking legal research of Robert D. Cook of the state attorney general’s office.

Undertaken in the absence of records burned when Gen. William T. Sherman’s army captured the capital in the Civil War, Mr. Cook’s research concluded that the 385-acre site is controlled by a charitable trust, and that all proceeds in a sale must go to DMH, to benefit mentally ill people. Initially, the General Fund was to receive half the proceeds of the sale, the terms of which were concluded in July.

It is just one example of Mr. Cook’s good work under five attorneys general. Mr. Cook recently was named South Carolina’s first solicitor general, serving as the leading attorney under the elected attorney general.

Mr. Cook has been with the office since 1977, working for attorneys general Daniel R. McLeod, Travis Medlock, Charles M. Condon, Henry McMaster and, now, Alan Wilson.

Mr. Wilson, who named Mr. Cook to the position, said the solicitor general’s role is to assist him in developing legal policy and navigating issues related to federalism and other constitutional matters. Mr. Cook continues to supervise the Opinion Section he has headed since 1983.

Mr. McMaster describes Mr. Cook, who also served him as special counsel during his eight years in office, as “absolutely indispensable” for his depth of knowledge about the state’s legal history and its constitution, with an institutional memory second to none.

“I have never seen anyone with a mind like his, with the scope, depth and logic,” Mr. McMaster tells us.

He cites the importance of Mr. Cook’s work on the Bull Street property, the Catawba River dispute and in opposition to the Legislature’s infamous 2004 “kitchen sink” bill.

Officially described as the Life Sciences Act, that legislation included an array of pork-barrel projects. Taxpayer advocate Edward Sloan brought suit against the Legislature, and that brought the attorney general’s office into play.

“Everybody expected us to defend the party line,” Mr. McMaster says. “But the responsibility of the AG’s office is to defend the constitution.”

Mr. McMaster argued and won that landmark case. Mr. Cook’s contributions were key in defining what is meant by legislative germaneness, and the case helped limit the odious and costly practice of “bobtailing,” or attaching pet projects to unrelated legislation.

Mr. Cook’s work also was instrumental to the successful resolution of the 2007-2010 dispute over the Catawba River, which was pending before the U.S. Supreme Court. A plan to divert more water in North Carolina would have seriously diminished the river’s flow to South Carolina, with disastrous results.

With Mr. Cook’s appointment, South Carolina joins some 30 states with a solicitor general.

The appointment reflects Mr. Cook’s long, leading role in the legal defense of the interests of the state and its citizens, and his outstanding work in that capacity.