It’s often said that nuclear weapons have protected nations from military attack.

But is there any solid evidence to bolster this contention? Without such evidence, the argument that nuclear weapons prevented something that never occurred is simply a counter-factual abstraction that cannot be proved.

Ronald Reagan -- the hardest of military hard-liners -- was not at all impressed by airy claims that U.S. nuclear weapons prevented Soviet aggression. Kenneth Adelman, a hawkish official in the Reagan administration, recalled that when he “hammered home the risks of a nuclear-free world” to the president, Reagan retorted that “we couldn’t know that nuclear weapons had kept the peace in Europe for forty years, maybe other things had.” Adelman described another interchange with Reagan that went the same way. When Adelman argued that “eliminating all nuclear weapons was impossible,” as they had kept the peace in Europe, Reagan responded sharply that “it wasn’t clear that nuclear weapons had kept the peace. Maybe other things, like the Marshall Plan and NATO, had kept the peace.” (Kenneth Adelman, The Great Universal Embrace, pp. 69, 318.)

In short, without any solid evidence, we don’t know that nuclear weapons have prevented or will prevent military aggression.

We do know, of course, that since 1945, many nations not in possession of nuclear weapons and not part of the alliance systems of the nuclear powers have not experienced a military attack. Clearly, they survived just fine without nuclear deterrence.

And we also know that nuclear weapons in U.S. hands did not prevent non-nuclear North Korea from invading South Korea or non-nuclear China from sending its armies to attack U.S. military forces in the ensuing Korean War. Nor did massive U.S. nuclear might prevent the Soviet invasion of Hungary, the Warsaw Pact’s invasion of Czechoslovakia, Soviet military intervention in Afghanistan, and the Iraqi invasion of Kuwait. Also, the thousands of nuclear weapons in the U.S. arsenal did nothing to deter the terrorist attacks of 9/11 on U.S. territory.

Similarly, nuclear weapons in Soviet (and later Russian) hands did not prevent U.S. military intervention in Korea, Vietnam, Lebanon, the Dominican Republic, Grenada, Panama, Afghanistan, and Iraq. Nor did Soviet nuclear weapons prevent CIA-fomented military action to overthrow the governments of Iran, Guatemala, Cuba, Chile, Nicaragua, and other nations.

Other nuclear powers have also discovered the irrelevance of their nuclear arsenals. British nuclear weapons did not stop non-nuclear Argentina’s invasion of Britain’s Falkland Islands. Moreover, Israel’s nuclear weapons did not prevent non-nuclear Egypt and non-nuclear Syria from attacking Israel’s armed forces in 1973 or non-nuclear Iraq from launching missile attacks on Israeli cities in 1991. Perhaps most chillingly, in 1999, when both India and Pakistan possessed nuclear weapons, the two nations -- long at odds -- sent their troops into battle against one another in what became known as the Kargil War.

Of course, the argument is often made that nuclear weapons have deterred a nuclear attack. But, again, as this attack never took place, how can we be sure about the cause of this non-occurrence?

Certainly, U.S. officials don’t appear to find their policy of nuclear deterrence very reassuring. Indeed, if they were as certain that nuclear weapons prevent nuclear attack as they claim to be, why are they so intent upon building “missile defense” systems to block such an attack -- despite the fact that, after squandering more than $150 billion on such defense systems, there is no indication that they work? Or, to put it more generally, if the thousands of U.S. nuclear weapons safeguard the United States from a nuclear attack by another nation, why is a defense against such an attack needed?

Another indication that nuclear weapons do not provide security against a nuclear attack is the determination of the U.S. and Israeli governments to stop Iran from becoming a nuclear weapons state. After all, if nuclear deterrence works, there is no need to worry about Iran (or any other nation) acquiring nuclear weapons.

The fact is that, today, there is no safety from war to be found in nuclear weaponry, any more than there was safety in the past produced by fighter planes, battleships, bombers, poison gas, and other devastating weapons. Instead, by raising the ante in the ages-old game of armed conflict, nuclear weapons have merely increased the possibility that, however a war begins, it will end in mass destruction of terrifying dimensions.

Sensible people and wise government leaders have understood for some time now that a more promising route to national and international security is to work at curbing the practice of war while, at the same time, banning its most dangerous and destructive implements. This alternative route requires patient diplomacy, international treaties, citizen activism, the United Nations, and arms control and disarmament measures. It’s a less dramatic and less demagogic approach than brandishing nuclear weapons on the world scene. But, ultimately, it’s a lot safer.