In the summer of 1951, a month after the Declaration celebrated its 175th anniversary, an unmarked panel truck pulled into the basement of the Library of Congress. Once loaded, it drove to the Maryland campus of the National Bureau of Standards, the government’s primary scientific facility. There the Declaration of Independence and Constitution were placed in the care of Gordon M. Kline, chief of the Plastics Section. Kline and his team had one focus: to create the most technologically sophisticated cases that science could envision to preserve these delicate parchments for posterity. Article continues after advertisement Kline’s mission had started before World War II. In 1940 Archibald MacLeish had charged the National Bureau of Standards with determining the best way to conserve the Declaration and Constitution. The war pulled the Bureau away from these efforts, but once peace returned, Kline and his scientists had gone back to work.…