‘Smiling Buddha’ was the codename for India's first nuclear bomb test in 1974. He must be grinning widely this week after Manmohan Singh, India's prime minister, reached a nuclear cooperation deal with US President George W. Bush.

The agreement would end a three-decade-old ban on US exports of nuclear technology or fuel to India. The United States will also move to amend international rules that permit nuclear exports only to countries that allow International Atomic Energy Agency (IAEA) safeguards on all their nuclear facilities. These rules were created in response to India's 1974 test, which used plutonium supplied by Canada.

A joint statement issued by Bush and Singh (see Nuclear deal riles India's researchers) said that “as a responsible state with advanced nuclear technology, India should acquire the same benefits and advantages as other such states”. The substitution of the phrase “nuclear weapons state” for “state with advanced nuclear technology” would have rendered the language more accurate, as the agreement is tantamount to a de facto admission of India into the established nuclear-weapons club of the United States, Russia, China, France and the United Kingdom.

The agreement between India and the United States seems to reflect the Bush administration’s desire to sideline the Non-Proliferation Treaty.

This is a very big deal. It flies in the face of the 1970 Nuclear Non-Proliferation Treaty (NPT). Under the treaty, states that were not already nuclear-weapons states agreed not to develop weapons, and in return are given access to nuclear-power technologies and fuels, under the oversight of the IAEA. As part of the bargain, the nuclear weapons states also agreed to progressively disarm.

India is not a member of the NPT, and it deserves some credit for the consistency of its nuclear policies. As early as 1955, it was calling unsuccessfully for a global ban on nuclear testing. Whereas Iraq and North Korea each signed the treaty and went on to surreptitiously attempt to develop nuclear weapons, India has refused to sign, arguing that existing nuclear powers should first demonstrate their commitment to reducing their own arsenals.

That is one reason why it would be simplistic to say that extending nuclear cooperation to India is fundamentally wrong. India has not acted outside international law. Arguably, if Britain and France can justify maintaining nuclear weapons, the world's largest democracy has a strong case for being accepted as a nuclear-weapons state.

Unlike its neighbour Pakistan, India has acted responsibly to prevent the proliferation of its own nuclear technology. The deal with the United States will also be a boon to the growth of India's nuclear power sector — although some Indian scientists fear that they may now become unnecessarily dependent on US technology. That is seen as a setback in a country that prides itself on its independent scientific and technical capacity (see India Outlook).

Nonetheless, the sight of Singh and Bush toasting India's nuclear future must have left Brazil, Argentina and South Africa — which each abandoned nuclear weapons and signed up to the NPT — feeling short-changed.

Indeed, the bilateral agreement between India and the United States could deal a hammer blow to the NPT. This May, a review conference of the treaty made little headway, and the latest agreement seems to reflect the Bush administration's desire to sideline the treaty altogether. In its place, the administration proposes non-proliferation à la carte, with the menu determined by the United States' ever-changing geopolitical interests.

Doubts about the feasibility of this approach should weigh heavily on the minds of US legislators as they consider the changes to existing law needed to implement the Bush–Singh agreement. The Indian deal may be defensible in its own terms — but the overall philosophy behind it is a recipe for further nuclear proliferation.