Donald Trump again is causing international consternation. His remarks about South Korea and Japan developing nuclear weapons set off a minor firestorm.

"It would be catastrophic were the United States to shift its position and indicate that we support somehow the proliferation of nuclear weapons to additional countries," argued deputy national security adviser Ben Rhodes.

Actually, what would be catastrophic is American involvement in a nuclear war as a result of its defense commitment to another nation, especially one able to defend itself.