There is no way to defend against an all-out nuclear war involving Russia, China and the United States, because each country possesses enough firepower to wipe out human civilization. But in a more limited conflict, involving a smaller number of intercontinental ballistic missiles from a rogue nation like North Korea, a military base in Alaska is a key part of America’s defense. VOA Pentagon correspondent Carla Babb gained exclusive access inside Clear Space Force Station, which houses America’s most sophisticated ground-based radar, and Fort Greely, near the Arctic Circle.