On the margins of a glitzy security event in Bavaria, the foreign ministers of France and Germany revived a dormant diplomatic format with China, in what was described as part of a larger effort to prevent the world’s superpowers from picking Europe apart. France’s Jean-Noel Barrot and Germany’s Johann Wadephul hosted China’s Wang Yi at the Munich Security Conference, reviving a configuration not seen since the days of French President Emmanuel Macron’s first term. “If we do not stick together,...