Opinion: U.S. should cut nuclear stockpile

Dr. Ira Helfand is the North American vice president of the International Physicians for the Prevention of Nuclear War, the organization that recieved the 1985 Nobel Peace Prize. Daryl G. Kimball is executive director of the independent Arms Control Association in Washington.

This week at an international nuclear security summit in South Korea, President Barack Obama's private request to Russian President Dmitry Medvedev for "space" on his proposal for cooperation on missile defense was overheard from a live microphone and grabbed the headlines.

The president's public remarks on the nuclear threat, however, were far more noteworthy. "The massive nuclear arsenal we inherited from the Cold War is poorly suited to today's threats, including nuclear terrorism," he told those in attendance. He announced that the administration is reviewing U.S. nuclear strategy and declared that we can "already say with confidence that we have more nuclear weapons than we need."

Now, Obama should put his words into action by discarding outdated nuclear war planning assumptions and opening the way toward deeper reductions in obsolete Cold War arsenals.

Changes are in order. The current size of both the U.S. and Russian arsenals -- and the fleet missiles, submarines, and bombers that carry them -- far exceeds what is necessary to deter nuclear attack. Both sides can and should go much lower.

Even under the 2010 New Strategic Arms Reduction Treaty, the United States and Russia can each deploy 1,550 strategic nuclear weapons on as many as 700 missiles and bombers until 2021 or beyond. Thousands of additional warheads are in reserve. Unless they adjust their thinking, both countries will spend hundreds of billions of dollars to modernize and maintain similar nuclear force levels for decades to come.

Obama shouldn't settle for marginal adjustments. Given that no other country deploys more than 300 nuclear weapons -- China possesses just 40 to 50 warheads on intercontinental-range missiles -- he should implement a significant reduction of the U.S. nuclear stockpile to just a few hundred deployed warheads.

During the Cold War, the United States and Russia amassed huge stockpiles to "prevail" in a protracted nuclear war. But such a conflict is extremely unlikely today -- and the size of the nuclear force required to deter an attack is also far smaller. Joseph Stalin or Mao Zedong might have been willing to sacrifice tens of millions of their countrymen in a nuclear exchange, but Vladimir Putin and Hu Jintao are not.

Speaking of the United States and the Soviet Union in his 1984 State of the Union address, President Ronald Reagan said, "The only value in our two nations possessing nuclear weapons is to make sure they will never be used. But then would it not be better to do away with them entirely?"

Until we eliminate nuclear weapons altogether, the United States can deter a nuclear attack with a smaller, but still lethal force of 500 or fewer strategic warheads.

A reliable and credible U.S. nuclear deterrent doesn't require immediate retaliation capabilities, but only the assurance that U.S. nuclear forces would survive a nuclear attack. As Obama correctly said in 2008, this requirement for prompt launch is "a dangerous relic of the Cold War. Such policies increase the risk of catastrophic accidents." He should eliminate the prompt launch requirement, which requires U.S. strategic nuclear forces to be prepared to retaliate in response to a nuclear attack immediately.

By discarding outdated nuclear thinking, the president can open the way for lower U.S.-Russian force levels, either through a new treaty or reciprocal and parallel cuts. The reductions would also enhance prospects for nuclear reductions involving other nuclear-armed states. And that would bring the ultimate goal -- the peace and security of a world without nuclear weapons -- closer to reality.