Welcome to 21st-century conflict, more Machiavellian than military, where hacks, leaks and fake news are taking the place of planes, bombs and missiles. The Russian interference in the United States presidential election is just a taste of more to come.

How can countries protect themselves from such methods? As with nuclear weapons, deterrence is better than confrontation. The United States and its allies in the West need to find a way to discourage Russia, the leading practitioner of this kind of political warfare, from striking first.

With nuclear weapons, deterrence relies on demonstrating the possession of similar capabilities — and the will to use them. This won’t work with political warfare.

It is not as though the United States hasn’t dabbled in destabilization and disinformation campaigns. But these tactics are less likely to work in Russia, where the news media is mostly state-controlled, the security apparatus quickly stamps out political threats, and citizens have few illusions about their leaders. (For example, when the Panama Papers revealed that President Vladimir V. Putin’s cronies had secret bank accounts, most Russians simply shrugged, unsurprised.) All that such efforts would do is show Russians that Mr. Putin is right to say the West is no better than him.