NEW DELHI, India — Days before President Barack Obama told the United Nations that he hoped to push through a universal treaty to ban all nuclear weapons testing by the end of 2010, a top Indian scientist threw New Delhi's security establishment for an atomic loop.

Kasturiranga Santhanam, the coordinator of India's 1998 nuclear tests, went public with allegations that India's much heralded Pokhran II test of a thermonuclear bomb 11 years ago was actually a fizzle.

“We are totally naked vis-a-vis China, which has an inventory of 200 nuclear bombs, the vast majority of which are giant H-bombs of power equal to three million tons of TNT,” Santhanam told reporters in New Delhi this week.

Naturally, the bizarre exercise in reverse brinkmanship (“About that bomb we told you we have...”) did not go down well. India's 1998 demonstration of thermonuclear capability — a

fusion-based, Hydrogen bomb — was the cause of great celebration in a country still fighting for a voice in global affairs and sandwiched between a belligerent, hereditary enemy in Pakistan and a frightening potential future adversary in China.

By calling its success into question, scientist K. Santhanam, who was director of test site preparations for Pokhran II, shook the country's confidence in its nuclear deterrent at a moment when the long, frustrating peace process with Pakistan seems as futile as ever.

But for the rest of the world, Santhanam's bombshell amounts to a colossal preemptive strike against Obama's push for the nations of the world to sign a Comprehensive Test Ban Treaty (CTBT) by the end of next year — not to mention a potentially debilitating assault on last year's Indo-U.S. civilian nuclear agreement. Already, opponents to the deal have begun echoing Santhanam's call for further testing of India's thermonuclear arsenal, and the lingering doubts about the efficacy of the country's bombs looks likely to tie Manmohan Singh's somewhat fragile coalition government's hands when the time comes to sign Obama's CTBT.

“We need to test again; it's just a question of when, not if,” said Bharat Karnad, a former member of India's National Security Advisory board and part of the group that drafted India's nuclear doctrine.

Of course, that may not have been true if Santhanam had kept his mouth shut. Since nuclear weapons are supposedly never to be used, whether the rest of the world believes they will work is more important than whether they actually do. And that's the simple fact that has flummoxed India's foreign policy experts, who are scratching their heads and asking, “Why now?” After all, Santhanam kept mum during the vociferous, three-year debate over the Indo-U.S. nuclear deal, which also mandates an end to testing. “[Now] the whole thing becomes unnecessarily subject to controversy and doubts and questions, and the public loses confidence in what the government is saying about the nuclear deterrent — which is totally pointless,” said Kanwal Sibal, who was foreign secretary in the BJP-led government that proceeded Singh's Congress-led coalition.

The Singh government subscribes to the theory that a “minimum deterrent” is sufficient to protect India from its nuclear neighbors, and even though that theory was predicated on the existence of a small number of effective thermonuclear missiles, most observers believe that Singh will not begin preparations of any kind for a resumption of testing. The big question is whether he can sell the country on agreeing to Obama's full-fledged moratorium.

Some say yes, others no.

“I cannot see India testing at all, unless the U.S. itself tests or China tests or Pakistan tests,” Sibal said. “Unilaterally testing makes no sense to me. The cost would be intolerable, not merely in terms of the Indo-U.S. nuclear deal, but we'd be isolated internationally. We'd be seen as wrecking the international nonproliferation regime for no good reason.”

“Manmohan Singh may not be inclined to test during his tenure, which is another four years,” Karnad said. “But the idea is to nevertheless keep the testing option open.”

The implications of both testing and not testing are murky.

Even if India never tests another nuke, Santhanam's accusation that Pokhran II was a fizzle isn't as damning as it might sound. For nuclear scientists, fizzle is a technical term for detonations that yield 30 percent less concussive force than expected, and Santhanam himself acknowledges that India's thermonuclear device yielded an explosion equivalent to 15 to 20 kilotons of TNT — the rub is that it was intended to generate 45 kilotons. The minimum deterrent lobby argues that's powerful enough to dissuade Pakistan from getting any crazy ideas, and even if India's nukes pale in comparison with China's, they're still devastating enough to give any rational adversary pause.

But for others, the niggling fear remains that doubts about the capacity of India's nuclear bombs make it all the more likely that one day it may have to use them. On the other hand, the global reaction to a new test is equally unpredictable. It would almost certainly spell an end to the Indo-U.S. agreement on civilian nuclear projects, and likely put its power projects with countries like France and Russia in jeopardy.

“I would expect that India would be placed in an international penalty box for some period of time and would be blamed for 'scuttling' efforts to bring a CTBT into force,” Henry Sokolski, executive director of the Nonproliferation Policy Education Center in Washington, confirmed in an email interview. The last time, India stayed in the penalty box for a decade, but U.S. sanctions prohibiting economic and military aid were waived after only a year.

The hawks in India's security establishment are growing more firm in their belief that the U.S. and Europe will not be comfortable isolating India from the global community for long this time, either, because it has emerged as Asia's only credible counterweight to China's growing military and economic might. “They might thrash about a bit and sound off a bit, but what option do they have?” Karnad said.

Apart from the paranoid, what developing nations hope to gain from their nuclear weapons is not so much security — though the contrasting treatment that the U.S. meted out to Iraq and Pakistan shows the value of deterrence in that realm — but a seat at the table. And that means Obama and the West have one big bargaining chip left to bring India into the nonproliferation fold: Sign the CTBT, get a seat on the U.N. Security Council.

Editor's note: This story has been updated to correct the explanation of thermonuclear capability.