Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. 'Unpredictability' is NATO's Greatest Challenge Stoltenberg Says Jela De Franceschi VOA Serbian service's Jela de Franceschi spoke with NATO Secretary General Jens Stoltenberg about the shifting global alliances in the current political environment. Q. Both sides of the Atlantic are undergoing political upheaval, unprecedented in a sense. We have impeachment proceedings in the U.S., the third time in modern American history, and we have Brexit in Europe, which has been a prolonged process. Does that affect larger security issues at all? Stoltenberg: I think what we have seen is that despite issues like these over decades on both sides of the Atlantic that NATO has proven that while we come to different opinions about Brexit and different opinions about the issues in the (impeachment) hearings in the Congress, we will continue to be a strong and adaptable alliance. That has happened so many times before. These important issues will not undermine NATO. .