Back when spies were spies, they spied by the rules—with the exception perhaps of those who did their spying for totalitarian regimes. The Constitution of the Soviet Union, for example, guaranteed the privacy of correspondence, but the government still read people’s private mail. By the end of the twentieth century, however, it seemed that most governments had finally stopped eavesdropping on their own citizens’ private correspondences.

But as David Kahn writes today in an Op-Ed piece for the New York Times:

President Bush’s ordering the National Security Agency to eavesdrop on Americans without warrants contradicts a long evolution toward the secrecy of communications. Centuries ago, people in England, France and the German states fought for the right to send letters without their being opened by the “black chambers” of absolutist monarchs. Martin Luther, whose letters had been opened by the Duke of Saxony, raged that “a thief is a thief, whether he is a money thief or a letter thief.”

As the author of The Reader of Gentlemen’s Mail, a biography of Herbert O. Yardley published by Yale University Press in 2004, David Kahn has written extensively on surveillance and intelligence gathering. Yardley was one of the most colorful and controversial figures in American intelligence, as famous for his indiscretions as he was for his achievements. In 1917, he established the nation’s first codebreaking agency, and his solutions helped the United States win a major diplomatic victory at the 1921 disarmament conference, but in 1929 his unit was shut down because “gentlemen do not read each other’s mail.”

How times change.