What the Use of Counterintelligence Letters Reveal About the Russia Investigation

Former FBI Director James Comey testifies before the Senate Intelligence Committee in the Hart Senate Office Building on Capitol Hill in Washington, D.C., on June 8, 2017. Chip Somodevilla/Getty Images

The New York Times reported on May 16 that the FBI had used national security letters and a “top secret” source to infiltrate the 2016 Trump presidential campaign, as part of its “investigation into the Trump campaign’s ties to Russia”—ties that, if proven, would presumably be criminal in nature.