How will history judge a generation of leaders who don't preserve the historical record? The revelation on Monday that Hillary Rodham Clinton used only a personal email account when she was secretary of state and did not preserve her emails on departmental servers seems to reflect a troubling indifference to saving the history she was living. Mrs. Clinton's aides eventually turned over 55,000 pages of correspondence. But the State Department's Office of the Historian estimates that the department produces two billion emails a year. The bigger problem is that the government produces an astounding volume of email, much of it classified, and the public doesn't get to see it unless archivists can preserve and process it. According to the nonpartisan Public Interest Declassification Board, a single intelligence agency is producing a petabyte of classified data every 18 months, or the equivalent of 20 million four-drawer file cabinets. The National Archives estimates that, without new technology to accelerate the process, that information would take two million employees a year to review for declassification. Instead, there are just 41 archivists working in College Park, Md., to review records from across the entire federal government - one page at a time. The government is producing more classified documents than it knows what to do with. The National Archives is buckling under the strain, and could collapse under an avalanche of electronic records. If it does, America's commitment to transparent governance will become a thing of the past, because the past itself will be impossible to recover.