When Russia's intelligence agencies obtained some of the National Security Agency's secrets about its own cyberweapons, it appeared to do so by manipulating a virus protection program sold by Kaspersky, a Russian firm.

State oil companies in Saudi Arabia, Africa, Iran, and Mexico have often been intelligence targets for the United States.

Back channels themselves are as old as American diplomacy. Thomas Jefferson was an early enthusiast - he often routed around his secretary of state, once sending a secret letter to the American envoy in France, Robert Livingston, that contained a coded message.

When confronted with a direct threat to American security, Obama has shown he is willing to act unilaterally - in a targeted, get-in-and-get-out fashion, that avoids, at all costs, the kind of messy ground wars and lengthy occupations that have drained America's treasury and spirit for the past decades.