Backed by American business, the United States aims to complete the remaining approvals for nuclear cooperation with India in roughly six months, but lingering questions could delay action, analysts said.
President George W Bush signed a law on Monday that represents a major step toward allowing India to buy US nuclear fuel and reactors for the first time in 30 years.
Beyond that, the 45-nation Nuclear Suppliers Group must change its rules governing nuclear trade; the International Atomic Energy Agency and Delhi must agree on a "safeguards" inspections regime. The US Congress must also approve a second law -- on technical details of the deal -- before US nuclear transfers to India can take place.
Undersecretary of State Nicholas Burns said the technical agreement, called a 123 agreement after a section of the US Atomic Energy Act, would be concluded "in the next few months" and "there aren't any major issues left to decide."
After that comes the IAEA plan for inspecting 14 of India's civilian nuclear plants and then the NSG rules change. Burns said: "I've talked to each one of those countries, and I'm confident that the Nuclear Suppliers Group will act."
NSG members Russia, Germany, Britain, France, and Japan and Australia have all announced support for nuclear cooperation with India, he said.
And after recent talks in Beijing, Burns concluded: "I do not believe the Chinese will block this."
He acknowledged that Ireland, Denmark, Norway, Sweden and Finland have doubts but hoped they would eventually join a consensus favoring changing the NSG rules.
The NSG prohibits trade with states that are not members of the nuclear Non-Proliferation Treaty and do not allow safeguards on all nuclear facilities -- India, Israel, and Pakistan.
Daryl Kimball of the Arms Control Association said India and the IAEA are still debating inspections, and consideration by the NSG may not proceed easily either.
India may accept safeguards only if the United States and others guarantee a steady nuclear fuel supply. Yet safeguards are meant to be permanent and this is underscored in the US law Bush signed, he said.
Under the law, US nuclear exports would be ended if India tested a nuclear weapon, as it did in 1998.
Kimball said countries skeptical about allowing a nuclear trade exception for India may suggest alternative proposals.
He wondered if the United States and China might try to cut deal under which China would allow nuclear trade with India if the NSG would at some point also permit nuclear trade with nuclear-armed Pakistan, India's rival and China's ally.
Bush rejected a nuclear cooperation agreement with Pakistan over blackmarket sales involving AQ Khan, father of Pakistan's nuclear programme, to Iran, Libya and North Korea.
Meanwhile, American companies are preparing to take advantage of a vast new Indian nuclear market worth $150 billion.
Seth Grae and Dennis Hays, top executives at Thorium Power Ltd., said they can't negotiate a final deal with India until the "123 agreement" is approved by Congress.
But they are in preliminary discussions on providing thorium technology for Indian fuel and reactor designs and could conclude a deal once Congress acts.
Thorium is a radioactive metal and the firm develops proliferation resistant nuclear fuel technologies.