India, Nov. 1 -- US President Donald Trump announced Wednesday night that the US will resume testing nuclear weapons for the first time since 1992. Just what kind of tests Trump envisages is not known, but his message was delivered hours ahead of his meeting with President Xi Jinping. A breakout of the informal global moratorium on nuclear testing would not be too far out for a President of the US (POTUS) who has trashed many other international norms, and plans to gut more. A resumption of nuclear tests could be a huge opportunity for India, if it can seize the moment. It is not a great secret that the Indian nuclear arsenal, which rests on its nuclear doctrine, has a deep flaw. This is its claim to possess a weapon that failed its only test. The thermonuclear weapon whose test took place on May 11, 1998, was, to quote K Santhanam, the man in charge of the Pokhran II tests, "a fizzle". But Santhanam only made the revelation in 2009, long after he had retired from the Defence Research and Development Organisation (DRDO) as well as the directorship of the Institute for Defence Studies and Analyses (IDSA) that he held till 2004. On May 11, 1998, India tested a 45 kiloton (kT) thermonuclear device, a 15 kT nuclear bomb as well as a 0.2 kT sub-kiloton device. On May 13, two more sub-kiloton tests were conducted. There had been questions about the thermonuclear tests in the wake of Pokhran II. For one thing, photographs of the test site showed a large crater at the site of the nuclear bomb test, but virtually none at the site of the allegedly more powerful thermonuclear one. In 2000, the doyen of Indian nuclear weapons scientists, PK Iyengar, who was then retired, had noted that according to the information he had, "the secondary (fusion) device burnt only partially, perhaps less than 10%". In September 2009, in an article in The Hindu, in the wake of the controversy stirred up by Santhanam's revelations, Ashok Parthasarathi and Sathanam repeated that "the yield of the second stage of the thermonuclear device tested in May 1998 was not only far below the design prediction made by the Bhabha Atomic Research Centre (Barc), but that it actually failed". It is not as though the Vajpayee government did not know this. In the wake of the tests, the DRDO report based on the on-site instrumentation and what is called a CORRETEX test, said as much. However, the Barc report claimed that the test was successful. Confirmation of the DRDO charge also came from an R&AW seismic monitoring facility maintained near Karnal, which had been set up in the 1960s with US help to monitor Chinese tests. The R&AW facility recorded the May 11 test as being around 20 kT, while if the thermonuclear test had been successful, the reading should have been three times that much. However, a political decision was taken to uphold the Barc report and declare the tests successful, because the government did not want to further rile the US at the time. Subsequently, too, in the wake of the 2009 Santhanam revelations, the then Manmohan Singh government, too, conveniently brushed the issue under the carpet and said that they had examined the evidence and found that the DAE was correct. There are important reasons for India to assure itself that it has a thermonuclear weapon that works, because it has also made a defensive "no-first-use" nuclear pledge. The doctrine officially released on January 4, 2003, declares that nuclear weapons will only be used in retaliation. This presumes that India could absorb the first attack and then hit back. To deter adversaries, the official doctrine has promised that "nuclear retaliation to the first strike will be massive and designed to inflict unacceptable damage". The kind of retaliatory damage that India promises can only be effected with the use of thermonuclear weapons, often called "city busters", a single weapon can devastate a city. Thermonuclear weapons are in orders of magnitude more powerful than nuclear weapons. They work in two stages: An ordinary nuclear weapon explosion is the trigger that sets off a fusion or a thermonuclear process, releasing vast amounts of energy that can give yields in several hundred kilotons and even several megatons. Right now, with its limited arsenal of 150 or so nuclear weapons, India lacks that capacity when we look at the threats we confront from China and Pakistan. While Pakistan's arsenal is the size of India's, China has been rapidly expanding and modernising its arsenal in recent years. There will be a huge irony if American actions trigger an Indian breakout from its moratorium. In 2007, India and the US signed the "123 Agreement" to enable the 2005 US-India Nuclear deal. But prior to agreeing to this, in 2006, the US Congress also passed the Hyde Act, which modified the US Atomic Energy Act to enable the 123 Agreement. But it contained an iron-clad condition that India would observe its unilateral moratorium on nuclear testing if it wanted to continue its cooperation with the US. Like India, the US has not signed the Comprehensive Test Ban Treaty (CTBT) of 1996, and like us, they observe a unilateral moratorium on testing. But the president of the US has the authority to resume testing under certain conditions. In line with this, the US maintains the ability to resume tests if the POTUS so decides. There have been some voices among former Trump officials advocating testing to maintain superiority over the Russian and Chinese arsenals. But, as usual, just what Trump has in mind in making his surprise announcement is not clear....