This Halloween, President Trump spooked the world by instructing his Department of War to restart nuclear testing. The US stopped underground explosive testing in 1992 after having conducted 1,030 nuclear tests. But Trump wants to restart it because he believes that Russia, China, the Democratic People’s Republic of Korea (DPRK), and Pakistan have been conducting nuclear tests. As he said, “I don’t want to be the only country that doesn’t test.”

Is FOMO the real reason for the president’s announcement? Have countries been conducting nuclear tests? The Chinese Ministry of Foreign Affairs has vehemently denied it, affirming that the country hasn’t broken the moratorium that it took upon itself in 1996 when it signed, though didn’t ratify, the Comprehensive Test Ban Treaty (CTBT). Pakistan too has denied the claim, stating that even as a CTBT non-signatory, it supports its objectives and purposes and that it “will not be the first to resume testing of nuclear weapons in South Asia.”

While Russia conducted the last of its 715 explosive tests in 1990, it has been engaged in sub-critical tests as allowed by the CTBT for the five NPT-recognised nuclear weapon states. Russia signed the CTBT in 1996 and ratified it in 2000—the only nuclear-armed state to do so. But, Moscow de-ratified it in 2023 to return to being at par with the US. Washington signed the CTBT in 1996 but hasn’t ratified it. In response to Trump’s statement, President Putin has ordered his officials to draft proposals for a possible commencement of nuclear weapons tests since he views this as necessary for maintaining global strategic parity.

As for DPRK, while Pyongyang has been threatening to conduct nuclear tests in recent years, its last test was in 2017. Meanwhile, an elaborate network of CTBTO monitoring stations and laboratories across 89 countries exists to verify explosive testing. Given this capability, there is little chance that countries could be clandestinely conducting explosive tests, especially since each of them, except DPRK, hosts monitoring stations.

Could President Trump be confusing the test of nuclear capable delivery vehicles with nuclear testing? His instructions for testing were given to the Department of War, not the Department of Energy. His Energy Secretary, the person in charge of nuclear testing, clarified that the reference was to non-critical explosions. Not many in the American strategic community believe that US has any technical, military, or political reasons to resume testing. Rather, doing so is likely to create security dilemmas by triggering similar actions elsewhere. Russia has already indicated as much. While China hasn’t said so, it does maintain a level of readiness at Lop Nor. So, if the US were to break the norm on nuclear testing, these two are likely to follow suit.

The US conduct of nuclear tests could open up the same possibility for India. In 1998, India had conducted five nuclear tests. These included designs of plutonium-based fission weapons with yields of 10 and 20 kT and sub-kiloton weapons of 0.2 and 0.6 kT. One of the designs was also that of a 45 kT thermonuclear device, which triggered a debate in 2009, with some Defence Research and Development Organisation (DRDO) scientists claiming that the test had failed to achieve the expected results. In his book, Nuclear Weapons and Indian Security: The Realist Foundations of Strategy, Bharat Karnad, a vocal sceptic of India’s thermonuclear capability, had already declared the low-yield thermonuclear test “a dud,” alleging that it had created “an insufficient data base” for “benchmarking computer simulations.” He maintains that “Indian scientists cannot reliably correct tested design, modify or refine it, nor change its power-to-yield characteristics, and even less upscale the design for much higher, leave alone megaton yields.”

These claims have been refuted by scientists involved in the 1998 Indian tests. Dr. R Chidambaram, former Chairman of the Atomic Energy Commission, emphasised that the thermonuclear test produced the stated yield as evident in the presence of sodium 22 and manganese 54, by-products of fusion rather than a pure fission reaction. The DAE claims that the H-bomb established the efficacy of the design concept. A September 2009 press statement by Dr. Anil Kakodkar and Dr. Chidambaram, both key players in the Pokhran-II tests, reiterated that “Thermonuclear weapons of various yields up to around 200 kt can be confidently designed on the basis of this test.”

Over the years, advances in real-time computational power, algorithmic sophistication, and data analysis have aided weapon improvements. Given India’s long experience in fusion and plasma physics, no adversary can risk taking its thermonuclear weapons lightly. Meanwhile, modern knowledge of how to detonate nuclear weapons at the optimum height for maximum effect has improved considerably. So, a number of strategically dispersed fission weapons too can cause high damage. In fact, nuclear weapons around 150-200 kT are deemed far more effective than megaton yields.

These facts assure the credibility of India’s nuclear deterrence. However, if the US does return to nuclear testing, India too could use the opportunity to enhance the military reliability of its warheads. Another round of hot testing to validate advanced nuclear designs could be especially fortuitous, especially at a time when China is expanding and modernising its nuclear capabilities. Following Washington, and possibly Moscow and Beijing, India would face the least likely (though not zero) diplomatic fallout. Legal eagles may bring up the relevant clauses from the India-US 123 Agreement of 2008, but the geopolitical conditions would be quite different after CTBT signatories have themselves conducted nuclear tests in violation of their own CTBT obligations.

It needs to be noted, though, that while additional tests may be desirable if international circumstances make them possible, they are not essential for the credibility of India’s nuclear deterrence. Additional tests could improve technical parameters and enable economies of fissile material and more compact warheads for ease of delivery with better yield-to-weight ratios. These technical considerations are important, but deterrence credibility is built on many other considerations that remain steadfast— irrespective of whether India gets to conduct more tests or not.

In fact, it would be best for the sake of international security if the US were not to open the Pandora’s box of nuclear testing. If it does so, other nuclear-armed states would follow suit: some like Russia for the sake of parity; China for strategic and military reasons; India, Pakistan, and North Korea for military reasons. Perhaps Israel, and Iran too, may find it prudent to use this window. Will such developments strengthen US security or undermine it? That is a calculation for Washington to make. Instead of a fresh round of nuclear testing, the US needs a fresh perspective on nuclear deterrence: one that can recall the damage caused by the use of one nuclear weapon of 10-12 kT on one city.

Dr. Manpreet Sethi is Distinguished Fellow, Centre for Aerospace Power and Strategic Studies (CAPPSS), New Delhi.