Undoubtedly, for nearly two decades, the most dangerous place on Earth has been the Indian-Pakistani border in Kashmir. It’s possible that a small spark from artillery and rocket exchanges across that border might—given the known military doctrines of the two nuclear-armed neighbors—lead inexorably to an all-out nuclear conflagration. In that case the result would be catastrophic. Besides causing the deaths of millions of Indians and Pakistanis, such a war might bring on “nuclear winter” on a planetary scale, leading to levels of suffering and death that would be beyond our comprehension.

Alarmingly, the nuclear competition between India and Pakistan has now entered a spine-chilling phase. That danger stems from Islamabad’s decision to deploy low-yield tactical nuclear arms at its forward operating military bases along its entire frontier with India to deter possible aggression by tank-led invading forces. Most ominously, the decision to fire such a nuclear-armed missile with a range of 35 to 60 miles is to rest with local commanders. This is a perilous departure from the universal practice of investing such authority in the highest official of the nation. Such a situation has no parallel in the Washington-Moscow nuclear arms race of the Cold War era.

When it comes to Pakistan’s strategic nuclear weapons, their parts are stored in different locations to be assembled only upon an order from the country’s leader. By contrast, tactical nukes are pre-assembled at a nuclear facility and shipped to a forward base for instant use. In addition to the perils inherent in this policy, such weapons would be vulnerable to misuse by a rogue base commander or theft by one of the many militant groups in the country.

In the nuclear standoff between the two neighbors, the stakes are constantly rising, as Aizaz Chaudhry, the highest bureaucrat in Pakistan’s foreign ministry, recently made clear. The deployment of tactical nukes, he explained, was meant to act as a form of “deterrence,” given India’s “Cold Start” military doctrine—a reputed contingency plan aimed at punishing Pakistan in a major way for any unacceptable provocations like a mass-casualty terrorist strike against India.

New Delhi refuses to acknowledge the existence of Cold Start. Its denials are hollow. As early as 2004, it was discussing this doctrine, which involved the formation of eight division-size Integrated Battle Groups (IBGs).  These were to consist of infantry, artillery, armor, and air support, and each would be able to operate independently on the battlefield. In the case of major terrorist attacks by any Pakistan-based group, these IBGs would evidently respond by rapidly penetrating Pakistani territory at unexpected points along the border and advancing no more than 30 miles inland, disrupting military command and control networks while endeavoring to stay away from locations likely to trigger nuclear retaliation. In other words, India has long been planning to respond to major terror attacks with a swift and devastating conventional military action that would inflict only limited damage and so—in a best-case scenario—deny Pakistan justification for a nuclear response.

Islamabad, in turn, has been planning ways to deter the Indians from implementing a Cold Start–style blitzkrieg on its territory. After much internal debate, its top officials opted for tactical nukes. In 2011, the Pakistanis tested one successfully. Since then, according to Rajesh Rajagopalan, the New Delhi–based co-author of Nuclear South Asia: Keywords and Concepts, Pakistan seems to have been assembling four to five of these annually.

All of this has been happening in the context of populations that view each other unfavorably. A typical survey in this period by the Pew Research Center found that 72 percent of Pakistanis had an unfavorable view of India, with 57 percent considering it as a serious threat, while on the other side 59 percent of Indians saw Pakistan in an unfavorable light.

This is the background against which Indian leaders have said that a tactical nuclear attack on their forces, even on Pakistani territory, would be treated as a full-scale nuclear attack on India, and that they reserved the right to respond accordingly. Since India does not have tactical nukes, it could only retaliate with far more devastating strategic nuclear arms, possibly targeting Pakistani cities.

According to a 2002 estimate by the US Defense Intelligence Agency (DIA), a worst-case scenario in an Indo-Pakistani nuclear war could result in 8 million to 12 million fatalities initially, followed by many millions later from radiation poisoning.  More recent studies have shown that up to a billion people worldwide might be put in danger of famine and starvation by the smoke and soot thrown into the troposphere in a major nuclear exchange in South Asia. The resulting “nuclear winter” and ensuing crop loss would functionally add up to a slowly developing global nuclear holocaust.

Last November, to reduce the chances of such a catastrophic exchange happening, senior Obama administration officials met in Washington with Pakistan’s army chief, General Raheel Sharif, the final arbiter of that country’s national security policies, and urged him to stop the production of tactical nuclear arms. In return, they offered a pledge to end Islamabad’s pariah status in the nuclear field by supporting its entry into the 48-member Nuclear Suppliers Group, to which India already belongs. Although no formal communiqué was issued after Sharif’s trip, it became widely known that he had rejected the offer.

This failure was implicit in the testimony that DIA Director Lieutenant General Vincent Stewart gave to the Armed Services Committee this February. “Pakistan’s nuclear weapons continue to grow,” he said. “We are concerned that this growth, as well as the evolving doctrine associated with tactical [nuclear] weapons, increases the risk of an incident or accident.”

Strategic Nuclear Warheads

Since that DIA estimate of human fatalities in a South Asian nuclear war, the strategic nuclear arsenals of India and Pakistan have continued to grow. In January 2016, according to a US congressional report, Pakistan’s arsenal probably consisted of 110 to 130 nuclear warheads. According to the Stockholm International Peace Research Institute, India has 90 to 110 of these. (China, the other regional actor, has approximately 260 warheads.)

As the 1990s ended, with both India and Pakistan testing their new weaponry, their governments made public their nuclear doctrines. The National Security Advisory Board on Indian Nuclear Doctrine, for example, stated in August 1999 that “India will not be the first to initiate a nuclear strike, but will respond with punitive retaliation should deterrence fail.” India’s foreign minister explained at the time that the “minimum credible deterrence” mentioned in the doctrine was a question of “adequacy,” not numbers of warheads. In subsequent years, however, that yardstick of “minimum credible deterrence” has been regularly recalibrated as India’s policymakers went on to commit themselves to upgrade the country’s nuclear-arms program with a new generation of more powerful hydrogen bombs designed to be city-busters.

In Pakistan in February 2000, President General Pervez Musharraf, who was also the army chief, established the Strategic Plan Division in the National Command Authority, appointing Lieutenant General Khalid Kidwai as its director general. In October 2001, Kidwai offered an outline of the country’s updated nuclear doctrine in relation to its far more militarily and economically powerful neighbor, saying, “It is well known that Pakistan does not have a ‘no-first-use policy.’” He then laid out the “thresholds” for the use of nukes.  The country’s nuclear weapons, he pointed out, were aimed solely at India and would be available for use not just in response to a nuclear attack from that country, but should it conquer a large part of Pakistan’s territory (the space threshold), or destroy a significant part of its land or air forces (the military threshold), or start to strangle Pakistan economically (the economic threshold), or politically destabilize the country through large-scale internal subversion (the domestic destabilization threshold).

Of these, the space threshold was the most likely trigger. New Delhi as well as Washington speculated as to where the red line for this threshold might lie, though there was no unanimity among defense experts. Many surmised that it would be the impending loss of Lahore, the capital of Punjab, only 15 miles from the Indian border. Others put the red line at Pakistan’s sprawling Indus River basin.

Within seven months of this debate, Indian-Pakistani tensions escalated steeply in the wake of an attack on an Indian military base in Kashmir by Pakistani terrorists in May 2002. At that time, Musharraf reiterated that he would not renounce his country’s right to use nuclear weapons first. The prospect of New Delhi being hit by an atom bomb became so plausible that US Ambassador Robert Blackwill investigated building a hardened bunker in the embassy compound to survive a nuclear strike. Only when he and his staff realized that those in the bunker would be killed by the aftereffects of the nuclear blast did they abandon the idea.

Unsurprisingly, the leaders of the two countries found themselves staring into the nuclear abyss because of a violent act in Kashmir, a disputed territory which had led to three conventional wars between the South Asian neighbors since 1947, the founding year of an independent India and Pakistan. As a result of the first of these in 1947 and 1948, India acquired about half of Kashmir, with Pakistan getting a third, and the rest occupied later by China.

Kashmir, the Root Cause of Enduring Enmity

The Kashmir dispute dates back to the time when the British-ruled Indian subcontinent was divided into Hindu-majority India and Muslim-majority Pakistan, and indirectly ruled princely states were given the option of joining either one. In October 1947, the Hindu maharaja of Muslim-majority Kashmir signed an “instrument of accession” with India after Muslim tribal raiders from Pakistan invaded his realm. The speedy arrival of Indian troops deprived the invaders of the capital city, Srinagar. Later, they battled regular Pakistani troops until a United Nations–brokered cease-fire on January 1, 1949. The accession document required that Kashmiris be given an opportunity to choose between India and Pakistan once peace was restored. This has not happened yet, and there is no credible prospect of it taking place.

Fearing a defeat in such a plebiscite, given the pro-Pakistani sentiments prevalent among the territory’s majority Muslims, India found several ways of blocking UN attempts to hold one. New Delhi then conferred a special status on the part of Kashmir it controlled and held elections for its legislature, while Pakistan watched with trepidation.

In September 1965, when its verbal protests proved futile, Pakistan attempted to change the status quo through military force. It launched a war that once again ended in stalemate and another UN-sponsored truce, which required the warring parties to return to the 1949 ceasefire line.

A third armed conflict between the two neighbors followed in December 1971, resulting in Pakistan’s loss of its eastern wing, which became an independent Bangladesh. Soon after, Indian Prime Minister Indira Gandhi tried to convince Pakistani President Zulfikar Ali Bhutto to agree to transform the 460-mile-long cease-fire line in Kashmir (renamed the “Line of Control”) into an international border. Unwilling to give up his country’s demand for a plebiscite in all of pre-1947 Kashmir, Bhutto refused. So the stalemate continued.

During the military rule of General Zia al Haq (1977–88), Pakistan initiated a policy of bleeding India with a thousand cuts by sponsoring terrorist actions both inside Indian Kashmir and elsewhere in the country. Delhi responded by bolstering its military presence in Kashmir and brutally repressing those of its inhabitants demanding a plebiscite or advocating separation from India, committing in the process large-scale human rights violations.

In order to stop infiltration by militants from Pakistani Kashmir, India built a double barrier of fencing 12 feet high, with the space between planted with hundreds of land mines. Later, that barrier would be equipped as well with thermal imaging devices and motion sensors to help detect infiltrators. By the late 1990s, on one side of the Line of Control were 400,000 Indian soldiers and on the other 300,000 Pakistani troops. No wonder President Bill Clinton called that border “the most dangerous place in the world.” Today, with the addition of tactical nuclear weapons to the mix, it is far more so.

Kashmir, the Toxic Bone of Contention

Even before Pakistan’s introduction of tactical nukes, tensions between the two neighbors were perilously high.  Then suddenly, at the end of 2015, a flicker of a chance for the normalization of relations appeared. Indian Prime Minister Narendra Modi had a cordial meeting with his Pakistani counterpart, Nawaz Sharif, on the latter’s birthday, December 25, in Lahore. But that hope was dashed when, in the early hours of January 2, four heavily armed Pakistani terrorists managed to cross the international border in Punjab, wearing Indian Army fatigues, and attacked an air force base in Pathankot. A daylong gun battle followed. By the time order was restored on January 5, all the terrorists were dead, but so were seven Indian security personnel and one civilian. The United Jihad Council, an umbrella organization of separatist militant groups in Kashmir, claimed credit for the attack. The Indian government, however, insisted that the operation had been masterminded by Masood Azhar, leader of the Pakistan-based Jaish-e Muhammad (Army of Muhammad).

As before, Kashmir was the motivating drive for the anti-India militants. Mercifully, the attack in Pathankot turned out to be a minor event, insufficient to heighten the prospect of war, though it dissipated any goodwill generated by the Modi-Sharif meeting.

There is little doubt, however, that a repeat of the atrocity committed by Pakistani infiltrators in Mumbai in November 2008, leading to the death of 166 people and the burning of that city’s landmark Taj Mahal Hotel, could have consequences that would be dire indeed. The Indian doctrine calling for massive retaliation in response to a successful terrorist strike on that scale could mean the almost instantaneous implementation of its Cold Start strategy. That, in turn, would likely lead to Pakistan’s use of tactical nuclear weapons, thus opening up the real possibility of a full-blown nuclear holocaust with global consequences.

Beyond the long-running Kashmiri conundrum lies Pakistan’s primal fear of the much larger and more powerful India, and its loathing of India’s ambition to become the hegemonic power in South Asia. Irrespective of party labels, governments in New Delhi have pursued a muscular path on national security aimed at bolstering the country’s defense profile.

Overall, Indian leaders are resolved to prove that their country is entering what they fondly call “the age of aspiration.” When, in July 2009, Prime Minister Manmohan Singh officially launched a domestically built nuclear-powered ballistic-missile submarine, the INS Arihant, it was hailed as a dramatic step in that direction. According to defense experts, that vessel was the first of its kind not to be built by one of the five recognized nuclear powers: the United States, Britain, China, France, and Russia.

India’s Two Secret Nuclear Sites

On the nuclear front in India, there was more to come. Last December, an investigation by the Washington-based Center for Public Integrity revealed that the Indian government was investing $100 million to build a top-secret nuclear city spread over 13 square miles near the village of Challakere, 160 miles north of the southern city of Mysore. When completed, possibly as early as 2017, it will be “the subcontinent’s largest military-run complex of nuclear centrifuges, atomic-research laboratories, and weapons- and aircraft-testing facilities.” Among the project’s aims is to expand the government’s nuclear research, to produce fuel for the country’s nuclear reactors, and to help power its expanding fleet of nuclear submarines. It will be protected by a ring of garrisons, making the site a virtual military facility.

Another secret project, the Indian Rare Materials Plant, near Mysore is already in operation. It is a new nuclear-enrichment complex that is feeding the country’s nuclear weapons programs, while laying the foundation for an ambitious project to create an arsenal of hydrogen (thermonuclear) bombs.

The overarching aim of these projects is to give India an extra stockpile of enriched uranium fuel that could be used in such future bombs. As a military site, the project at Challakere will not be open to inspection by the International Atomic Energy Agency or by Washington, since India’s 2008 nuclear agreement with the United States excludes access to military-related facilities. These enterprises are directed by the office of the prime minister, who is charged with overseeing all atomic-energy projects. India’s Atomic Energy Act and its Official Secrets Act place everything connected to the country’s nuclear program under wraps. In the past, those who tried to obtain a fuller picture of the Indian arsenal and the facilities that feed it have been bludgeoned into silence.

Little wonder then that a senior White House official was recently quoted as saying, “Even for us, details of the Indian program are always sketchy and hard facts thin on the ground.” He added, “Mysore is being constantly monitored, and we are constantly monitoring progress in Challakere.” However, according to Gary Samore, a former Obama administration coordinator for arms control and weapons of mass destruction, “India intends to build thermonuclear weapons as part of its strategic deterrent against China. It is unclear, when India will realize this goal of a larger and more powerful arsenal, but they will.”

Once manufactured, there is nothing to stop India from deploying such weapons against Pakistan. “India is now developing very big bombs, hydrogen bombs that are city-busters,” said Pervez Hoodbhoy, a leading Pakistani nuclear and national-security analyst. “It is not interested in…nuclear weapons for use on the battlefield; it is developing nuclear weapons for eliminating population centers.”

In other words, as the Kashmir dispute continues to fester, inducing periodic terrorist attacks on India and fueling the competition between New Delhi and Islamabad to outpace each other in the variety and size of their nuclear arsenals, the peril to South Asia in particular and the world at large only grows.