Julian Borger in Washington Friday April 12, 2002 The Guardian
The Bush administration is contemplating the use of nuclear warheads on the intercepters it hopes will protect the US from attack as part of its planned missile defence system.
William Schneider, the Pentagon's top scientific adviser, told the Washington Post that he had been encouraged by the defence secretary, Donald Rumsfeld, to re-examine the feasibility of nuclear-tipped intercepters, nearly 30 years after the idea was abandoned as technically and politically unacceptable.
It is the latest in a series of signs that the Bush team is radically rethinking the role of nuclear weapons in its arsenal, in a way that its critics believe will blur the distinction between conventional and nuclear warfare.
Late last year the Pentagon produced a nuclear posture review which called for research into low-yield "mini-nuke" bombs for use as tactical weapons to penetrate enemy underground bunkers.
Mr Schneider said that Mr Rumsfeld had asked the board to think "outside the box" on missile defence. "We've talked about it as something that he's interested in looking at," he said.
The system being tested relies on "hit-to-kill" technology by which intercepters destroy incoming missiles by force of impact rather than by detonation.
This approach presents enormous technical problems in programming the intercepter to ignore decoy war heads and hit the live missile.
A nuclear explosion in space would destroy everything in the vicinity, including chemical and biological warheads, Mr Schneider pointed out.
Apart from the risk of accidents, electromagnetic shock waves and ionized clouds, a nuclear blast in space could also disable communications satellites and knock out ground-based electronics.
These potential problems caused research into nuclear intercepters in the mid-1970s to be shelved.
"It seems to be a sign of desperation that they cannot solve the problem of the hit-to-kill programme of distinguishing targets from decoys," Henry Kelly, president of the Federation of American Scientists, said.
"It was rejected three decades ago for very good reason: a one megaton explosion would knock out a great number of satellites, and that is obviously much more of a problem now than it was then."
Mr Bush decided in December to withdraw from the 1972 anti ballistic missile (ABM) Treaty, which presented an obstacle to research and tests of the embryonic missile defence system. He also accelerated the timetable for missile defence deployment, making 2004 the deadline for the deployment of a basic system.
The US conducted its latest test of the "hit-to-kill" intercepter last month over the Pacific, scoring a direct hit on a dummy incoming missile. The Pentagon hailed the test as a success, pointing out that it was the fourth hit in six tries.