A Charleston County councilman had wanted to withhold some funding from the Charleston school unless the flag was removed.
An opinion issued Tuesday by state Solicitor General Robert Cook concludes the flag is protected by the state's Heritage Act of 2000. That law protects monuments and memorials on public property dedicated to any war in which the state fought. It also protects memorials to African American or Native American history.
Citadel Board of Visitors Chairman Michael Steele said in a statement that while the flag brings up strong emotions, the school hopes the opinion will bring closure to the issue.