BERLIN — As in a game of chess, there are geopolitical moves through which a country can, unwittingly, checkmate itself. Opening a debate on German nuclear weapons would be such a move. Yet, this is exactly what some Germans have recently proposed.

Which emerging threat is the world missing right now? After a truly horrendous year for international peace and security, this question will be even more important for the leaders, analysts and media gathering last week at the 51st Munich Security Conference (MSC). A year ago,