It was 74 years ago that the United States became the first and only country ever to use nuclear weapons in war, detonating two bombs over Hiroshima and Nagasaki and ending the Pacific campaign in World War II.

The destructive power of those bombs made nuclear weapons the sine qua non of strategic power, which inevitably led to an arms race and to dangerous proliferation. Today, it is the bad guys such as North Korea, Iran, and terrorist organizations that pose a nuclear threat.