The United States has the most robust intelligence apparatus in the world. We’ve got officers working in the field, people monitoring and analyzing all manner of signals, and an enormous infrastructure to help facilitate everything from logistics to politics. But often we rely upon foreign sources on the ground, embedded everywhere from al-Qaida’s ranks to Russian President Vladimir Putin’s office — and in return for their service, the U.S. sometimes rescues them when they’re at risk of being caught. So what happens to foreign spies once they defect? That’s where the National Resettlement Operations Center comes in. Yahoo News National Security and Investigations Reporter Jenna McLaughlin explains.