Pressure is quietly mounting on John McCain to support the idea of a nuclear-free world. It is being pushed primarily by former secretaries of state, and Senator McCain advisers, Henry Kissinger and George Shultz.

They are joined in their efforts by a bipartisan slate of eminent national security figures, including a former secretary of defense during the Clinton administration, William Perry, and a Democratic Party heavyweight, Sam Nunn. Hillary Clinton and Barack Obama have already signaled their support for the effort.

The Kissinger-Shultz argument says that in today’s world where nuclear weapons are both becoming more dangerous and are being procured by rogue states — whose smaller arsenals and radical ideologies mean that the Cold War-era Mutually Assured Destruction calculation is unlikely to apply — it is far more likely that nuclear weapons will be used. Therefore, they argue, the only way to make the world safe is to remove all nuclear weapons. And so Messrs. Kissinger and Shultz support the introduction of new measures to get the Nuclear Non-Proliferation Treaty back on track.

In other words, America is just as bad as Iran for having nuclear weapons. The argument assumes that the problem with nuclear weapons is not who has them, but having them in the first instance. If this logic is accepted, our efforts to disarm North Korea and Iran will become far more difficult. Such regimes will be able to demand more reasonably (they’ve already been using this argument) that they will only disarm when we fully disarm.

Equating the sheriff with the outlaw is a mistake. America’s nuclear arsenal serves an important security function: Rogue regimes are unlikely to risk an altercation knowing that America can hit back much harder. Nuclear weapons in the right hands serve as a crucial deterrent.

Israel’s perceived nuclear program, for example, causes enemies such as Syria and Iran to think twice before striking. Erasing Israel’s nuclear advantage only would give us a more volatile Middle East. The American people are unlikely to be safer by taking nuclear weapons away from America and Britain.

By supporting this proposal, both Senators Obama and Clinton are undermining the arguments with which they have attempted to undermine each other: That they either have the necessary experience, or have made the right decisions in the past, on crucial issues of national security. Because if there is one lesson we have learned again and again, it is that we cannot trust rogue regimes to disarm.

Just ask President Clinton. Under his watch, while he was busy trusting and negotiating with Iran, the mullahs were exposed by an opposition group for lying for almost two decades about their nuclear program. Even after that, as the recent National Intelligence Estimate on Iran’s nuclear program showed, as President Clinton tried trusting them again and was negotiating with the then (“reformist”) president of Iran, Mohammad Khatami, the Iranians were secretly continuing their program.

The likelihood is that democracies would disarm in good faith, while rogue regimes would secretly continue their programs. It appears that if there is another Democratic president we will make the mistake for a third time.

In pursuing this agenda, Secretaries Kissinger and Shultz are continuing to deal with problems leftover from the Cold War. But the focus on legacies forgets today’s problems. Their plan is a good one if our only concern was Russia. But today’s threat is not just Russia’s nuclear weapons. Today, we also must pay attention to North Korea’s proliferation, Iran getting the bomb, and terrorists getting their hands on nuclear weapons.

In addition, simply reducing our arsenal increases the likelihood of a nuclear war. Smaller arsenals actually add to the chance of first use. To enemies they appear easier to destroy in one go, and so the incentive is raised. For the same reason they also increase the incentive to conduct preventative strikes. And if we have a smaller nuclear arsenal, a rogue regime with a small arsenal will carry more weight — increasing the incentive for them to pursue a program in the first instance.

The goal of pursuing a nuclear-free world is a noble one. When the likes of Henry Kissinger and George Shultz throw their weight behind a program it takes a brave person to stand in their way. But until Iran and North Korea end their destructive ways, it will take quite the politician to convince the American people that the threat lies in America, Great Britain, and Israel not having nuclear weapons. Senator McCain should welcome having this debate with Senators Obama and Clinton.

Mr. Freedman was the foreign policy analyst and a speechwriter for Mayor Giuliani’s presidential campaign.