Redevelopment of the area north of Pennsylvania Avenue became one of Secretary of the Interior Stewart Udall's highest priorities. The plan called for demolition of most of the existing structures north of Pennsylvania Avenue, but exercise of the government's powers of eminent domain would require (it was believed) creating a special designation for the area. In January 1965, the government proposed putting the entire area envisioned for redevelopment under the control of the National Park Service. According to historian Robert M. Utley, Secretary Udall and architect Nathaniel Owings drew the boundaries of the Pennsylvania Avenue National Historic Site according to the needs of Owing's plan. Further investigation, however, revealed that the Historic Sites Act of 1935 required a study of the area's national significance and a finding by the National Park System Advisory Board. Utley, then an Interior Department historian, was summoned to make these findings, but advised Udall that the Historic Sites Act was intended to preserve (not tear down) old buildings and that the drawings of the site's boundaries would have to follow the historical findings rather than define them. When Utley was advised that Udall was unhappy with his assessment, Utley quickly backtracked. Utley quickly assembled a panel of historians and produced as much research on the area within the Owings boundaries as he could. Although the Utley panel found that much of historical significance had occurred within the Owings boundaries and that a number of historic buildings still existed within the proposed site, there was little to support designation of the area as a historic district. Nonetheless, the advisory board ignored this weakness in the study, and approved the designation of the historic site.