My How Things Have Changed (NSA Edition)

From Stephen Kirzner's new important book about John Foster and Allen Dulles, The Brothers:

[At the time of World War I] few in Washigton had ever paid much attention to collecting intelligence about other countries, either because they believed the United States did not need it or because of the notion that, as a previous secretary of state, Henry Stimson, memorably put it, "gentlemen do not read each other's mail."