The deletions began shortly after Donald Trump took office. C.D.C. web pages on vaccines, H.I.V. prevention, and reproductive health went missing. Findings on bird-flu transmission vanished minutes after they appeared. The Census Bureau’s public repository went offline, then returned without certain directories of geographic information. The Department of Justice expunged the January 6th insurrection from its website, and whitehouse.gov took down an explainer page about the Constitution. On February 7th, Trump sacked the head of the National Archives and Records Administration, the agency that maintains the official texts of the nation’s laws, and whose motto is “the written word endures.”