The United States wants to pivot to Asia, but the Middle East keeps getting in the way. Likewise, India wants to pivot to China, but Pakistan keeps getting in the way. Pakistan matters to India for two primary, interconnected reasons: its home-grown terrorists and its nuclear-weapon programs. The pathway to crisis and war on the Subcontinent begin with the actions of violent extremist groups based in Pakistan. As long as this pathway remains open, deterrence stability does not improve with nuclear modernization programs. Instead, stability is dependent on Indian restraint after severe provocation.

The nuclear competition between Pakistan and India now qualifies as a serious arms race. Since the 1998 tests, when both expressed fealty to credible, minimum deterrence, they have flight-tested fourteen types of nuclear-capable missiles. Both countries have embraced cruise missiles and sea-based capabilities. Pakistan advertises its short-range Nasr missile as being nuclear-capable. If Pakistan’s military leaders have established a requirement for a nuclear-tipped Nasr, they could employ the same logic to produce other types of battlefield nuclear weapons as well.

Both countries have recently flight-tested longer- as well as shorter-range ballistic missiles. India can now reach targets throughout China. Pakistan can reach targets in all of India – and the Middle East. India and China have the means to place multiple warheads atop some of their missiles and to deploy limited ballistic missile defenses. The flight-testing and induction of MIRVs, even on a small scale, would have ripple effects in Pakistan, as would the deployment by India of limited ballistic missile defenses.

Since the 1998 tests, India and Pakistan have fought one limited war, experienced one crisis sparked by an attack on the Indian Parliament building that triggered full-scale mobilizations, and another crisis resulting from a mass slaughter in Mumbai. It’s been seven years between crises and seven years since the last crisis. There has been no progress on the diplomatic front, no movement to resolve the Kashmir dispute and no agreement to set it aside. There has been no significant increase in direct cross-border trade, and still no direct trade between Karachi and Mumbai. The last nuclear risk-reduction measure negotiated by India and Pakistan was in 2007.

Government officials in India and Pakistan seem unable to ameliorate the arms race unfolding on the Subcontinent. New Delhi is troubled by China’s strategic modernization programs. Initiatives to improve relations with Pakistan are hard to pursue when the “mastermind” of the Mumbai attacks, Zaki ur-Rehman Lakhvi, receives a get-out-of-jail-free card. Prime Minister Nawaz Sharif finds it hard to take initiatives with India that his military leadership opposes. All of which means that not much has changed with respect to the causes of potential conflict on the Subcontinent since the 1998 tests. But much has changed with respect to the consequences of potential conflict, given the enlarged and diversified nuclear arsenals now in place.

The Stimson Center has published a new collection of essays, Deterrence Instability and Nuclear Weapons in South Asia, to call attention to these developments. China figures prominently in these pages, but our focus is on India and Pakistan, where the potential for conflict is greatest. The nuclear arms competition between India and Pakistan spells trouble ahead – especially in the absence of sustained, top-down efforts to improve ties.

The circumstances for another serious crisis between India and Pakistan remain in place. The Pakistani military’s laudable counter-terrorism efforts in the tribal belt will garner no sympathy if the Lashkar e-Toiba or another Punjabi-based group carries out spectacular acts of violence against India. In this event, all eyes will be on Prime Minister Modi, who is a “decider” rather than an agonizer, like his predecessors. He may decide, as A.B. Vajpayee, Sonia Gandhi, and Manmohan Singh did, that India’s economic growth is of paramount importance and that it’s not worth fighting another war with Pakistan. In which case, Pakistan would once again lose while India continues on its path of accumulating power. Or he may decide to hit back, in which case both Pakistan and India could lose quite a lot.

Michael Krepon is Co-Founder of the Stimson Center. This piece originally ran in Arms Control Wonk on May 4, 2015.