US moves from nuclear arms to conventional missiles with global reach

While President Barack Obama speaks overseas of his vision of a world without nuclear weapons, his military commanders at home are quietly accelerating a programme to develop and deploy a new class of conventional intercontinental ballistic missiles which will have the capacity to strike targets anywhere in the world within an hour.

While the effort to develop the new missile capability, called Prompt Global Strike, began in the late 1990s and through the Bush years, President Obama has expanded its budget with hopes that it can be added to US military's array of options by the middle of this decade. First prototype tests will be carried out by the Air Force next month.

American commanders envisage a missile that will travel at hypersonic speeds, in part outside of the Earth's atmosphere, with the ability to strike a target anywhere around the globe within one hour from launch with a conventional but still potentially devastating explosive payload.

Even as Moscow has agreed to the arms control treaty signed yesterday, it has become increasingly loud in warning of the dangers of the new global missiles under development by the Pentagon. "World states will hardly accept a situation in which nuclear weapons disappear, but weapons that are no less destabilising emerge in the hands of certain members of the international community," Russian Foreign Minister Sergei Lavrov said earlier this week.

Nuclear deterrence has been the key plank of US defence policy for six decades but while Washington views the new conventional weaponry as key to protecting America in a post-Cold War world where the threats may come not just from nations but also from terror networks, critics argue that they present new and important risks. Most commonly cited is the danger that other countries, including China and Russia, could mistake one of them for a nuclear missile unless they are fired at sufficiently low altitude. Once they are launched, there could be difficulty in distinguishing their conventional payloads from nuclear ones. That in turn could accidentally trigger a nuclear retaliation by Russia or another similarly-armed power.

Another danger is that if nuclear weapons are no longer at issue, there would be a bigger temptation for American military commanders to become more cavalier about ordering strikes. And unless intelligence can be fully relied upon, the chances of striking mistaken targets are high.