The Pentagon is considering replacing the nuclear warheads on some ballistic missiles with conventional munitions so that they can be used for "pre-emptive" strikes against terrorists, Defence Secretary Donald Rumsfeld told reporters after a meeting with Russia's Defence Minister Sergei Ivanov.

"If either of our countries or friends and allies were threatened at some number of years into the future with a weapon of mass destruction or a capability that was that lethal, I think any president, whether of Russia or the United States, would like to have available a conventional weapon that could attack that target swiftly and accurately and precisely and not feel that the only thing they had might be a nuclear weapon, which they would not want to use.", Rumsfeld said. He urged Russia to consider the idea too, but Ivanov said a pre-emptive strike was not the only solution.

The Pentagon has considered such strategies before; in February 2003 a similar plan was suggested, and in May 2006 it was recommended that Submarine-Launched Ballistic Missiles (SLBMs) be used for such a purpose. Critics wondered what the risks would be for setting off accidental nuclear war: it would be impossible for another nation to tell whether a Trident II or Minuteman III launch was conventional- or nuclear-armed until it had actually detonated.