A few weeks after leaving office, former Secretary of State Hillary Clinton may have breathed a sigh of relief and reassurance when Director of National Intelligence James Clapper denied reports of the National Security Agency eavesdropping on Americans. After all, Clinton had been handling official business at the State Department like many Americans do with their personal business, on an unsecured server. In sworn testimony before the Senate Intelligence Committee on March 12, 2013, Clapper said the NSA was not collecting, wittingly, “any type of data at all on millions or hundreds of millions of Americans,” which presumably would have...