Historic preservationists and members of Idaho's tribes oppose covering the 75-year-old murals that were commissioned as part of a Depression-era program to help put artists to work, arguing that the public can learn from history's mistakes. Twenty-six murals were painted in southern California and mounted in the former Ada County courthouse in 1940. Because the murals are installed as part of the historic building's staircase wall, the state is banned from tampering or destroying the paintings. Lawmakers, historians and tribal members came to a solution by spending months — described as painful on Wednesday — working on appropriate explanatory language to post on plaques under the murals to offer historical context to the images.