NATO is facing ... one of its most difficult crises in seven decades. It is not a crisis of military strength or readiness. The Alliance is preserving the peace in Europe and containing an assertive Russia. It is not a crisis of relevance. NATO troops continue to serve in Afghanistan, in the fight against the Islamic State, in preserving the peace in Kosovo and in providing security in the Atlantic, Mediterranean, Black Sea, Baltic Sea and Balkan regions. It is assisting the EU in managing the migration crisis through its maritime capacity. The allies also remain with us in NATO’s most important mission—the defense of free, democratic countries in North America and Europe. The crisis is one of allied trust and confidence in America’s leadership of NATO.
Burns, R. Nicholas. "Full Committee Hearing Assessing the Value of the NATO Alliance." Testimony before the United States Committee on Foreign Relations, September 5, 2018.