Until last Monday there were still only five "official" nuclear powers, defined by the Non-Proliferation Treaty as those that were nuclear before 1968: the US, Russia, Britain, France and China. A sixth, Israel, was "nuclear opaque" - everyone knew it had nuclear weapons but it had never officially said so.
The break-up of the Soviet Union briefly gave nuclear weapons to Belarus, Kazakhstan and Ukraine but they all, commendably, gave them back to Russia. South Africa probably had nuclear weapons but gave them up, partly because the threat of a Soviet amphibious landing had gone and partly to keep them from the ANC.
Then there were "threshold powers", of which India was one, along with Pakistan and North Korea in the front rank. Brazil and Argentina were not far behind, but both voluntarily stopped developing nuclear weapons. Finally there are the "pariah states": Iraq, Iran and Libya. With Iraq firmly under observation, Iran - with its contacts with North Korea, Russia and China - may be the most likely to get nuclear weapons soon.
The concept of "official" nuclear powers has long made little sense. Israel has about as many nuclear weapons - perhaps 100 - as Britain, and is believed to have deployed them in the 1973 war. India set off a "peaceful" nuclear explosion in 1974; at least the latest test reports were unequivocally described as helping it to develop operational nuclear weapons.
Pakistan has also long been "nuclear capable". The arrival of a US delegation to persuade it not to emulate India suggests that the Pentagon and the CIA believe it to be as capable as India, though able to assemble fewer warheads: 15 to 20, against a probable 60. The two have long planned for war in nuclear conditions: their emphasis on tank warfare owes much to the belief that tanks are the best way of getting around a nuclear battlefield.
Dr Bellamy is Reader in Military and Security Studies at Cranfield University.Reuse content