How should the US and European leaders respond? Historically, phases of resurgent radicalism have lasted 5-10 years, marked by greater aggressiveness against internal and external enemies.
美国和欧洲的领导人应该如何应对呢？从历史上看，激进主义复活的阶段会持续5到10年，标志是对国内外的敌人采取更具侵略性的行动。