The Associated Press reports: The top U.S. intelligence chief, James Clapper, said this week that the loss of state secrets as a result of leaks by former National Security Agency analyst Edward Snowden was the worst in American history. Clapper backed up his assertion with dire forecasts about emboldened enemies abroad, but some historians and researchers said the U.S. has struggled with even more devastating intelligence breakdowns over the past century.

Clapper, the director of national intelligence, has said Snowden’s disclosures and the resulting media coverage are giving away blueprints for surveillance programs. “Terrorists and other adversaries of this country are going to school on U.S. intelligence sources, methods and tradecraft,” he told the Senate Intelligence Committee on Wednesday.

At the start of that hearing, Clapper staked a claim he had not previously made in public. Snowden’s leaks, he said, were “the most massive and most damaging theft of intelligence information in our history.”

Historians and researchers said Clapper’s remark ignores the most devastating intelligence loss of the 20th century — the theft of America’s top-secret atomic bomb design by Soviet spies. Others say a trio of Americans who spied for Russia in the 1980s and 1990s — Aldrich Ames, Robert Hanssen and John Walker — caused immense intelligence damage that led to the loss of vital secrets and the deaths of American informants. [Continue reading…]