Today the United States has 4,600 nuclear weapons, and is planning to spend up to $1 trillion over the next 30 years refurbishing them. But in the post-Cold War era, is that really necessary?

Admiral Cecil D. Haney, head of the U.S. Strategic Command, says it is.

“We have to maintain strategic stability as a first and foremost principle," Haney said.

There are a number of ways nuclear weapons do this, he says. The first one is the most obvious—they deter our enemies (e.g., North Korea) and frenemies (e.g., Russia) from doing anything truly catastrophic.

But there’s also an important effect nukes have on our allies, Haney says.

“We don’t want the allies we provide assurance to, and what have you, to decide that they want to develop their own capability,” he said. “That would be a bad state of affairs.”

In other words, a strong nuclear stockpile may actually do more to prevent proliferation than it does to perpetuate it.

Or, as Donald Trump once put it, “With nuclear, the power, the devastation is very important to me.”