At best, therefore, the extra defences can offer a little bit of extra insurance in a crisis, by helping to persuade an aggressor that an attack, or a threatened one in an attempt at nuclear blackmail, might well fail and invite retribution instead.

• 因此，新的防御系统能够充其量使那些挑衅者明白一次进攻或者核讹诈威胁很难得逞，甚至很有可能招致反击，这样能在危难时刻提供些许额外的安全保障。