While diplomacy is still the “preferred course of action,” he warned of an “effective and overwhelming” U.S. military response should dialogue not be enough. “Make no mistake—any attack on the United States or our allies will be defeated,” he said. “I cannot imagine a condition under which the United States will accept North Korea as a nuclear power,” he said. Mattis’ comments come after Pyongyang’s Foreign Minister Ri Yong-Ho said last month that North Korea could soon test a nuclear bomb over the Pacific. Read more at BBC.