Back in the late 1990s, Ashley Tellis characterised South Asia’s nuclear balance as ‘ugly stability ^[1]’—a condition, he believed, that would probably last for a decade and perhaps longer.

This peculiar form of stability derives substantially from the inability of both India and Pakistan to attain what may be desired political objectives through war. Consequently, premeditated conventional conflicts will remain absent for some time to come, though security competition will continue through subconventional violence waged with varying levels of intensity … [T]his stability will be “ugly” in that it entails a relatively high degree of subconventional violence on at least one side, perhaps both.

So, 2019’s a long way from the late 1990s, but the concept of ugly stability is still applicable to South Asia. Indeed, in its broad dimensions, it seems to be increasingly relevant to the future global nuclear order as well.

Many readers might find that unsettling, especially those who like their nuclear orders finely-wrought, as a managed system ^[2] of deterrence interlinked with a managed system of abstinence, for example. Western publics typically undervalue deterrence and overvalue arms control agreements, in part because they see those agreements as the principal barrier to nuclear war. Hence their anxiety about disruption in the arms-control world. And, because most Western states are democracies, that anxiety translates into pressure on Western governments to ‘fix’ problems in nuclear arms control, even when those problems aren’t theirs to fix.

That view’s wrong, of course. Yes, arms control agreements bring a level of detail and reassurance to nuclear relationships. And they might properly be seen as early-warning indicators of looming difficulties in those relationships—mainly the US–Russia nuclear relationship, because that’s the foundation for much of the current arms control architecture. Still, it isn’t the management of nuclear deterrence that’s the principal barrier to war, but deterrence itself. Similarly, it isn’t the management of nuclear abstinence that stops proliferation, but abstinence itself—for most states, the simple judgement that proliferation isn’t in their interests.

When managed stability falters, the result isn’t unmanaged instability. Rather, it might be better described as unmanaged stability—or what Tellis would call ugly stability. And ugly stability has a value of its own: it works when other systems don’t. The South Asian nuclear balance doesn’t work by carefully-measured arms control agreements. Its ‘stability’ derives from other factors, including: each side’s constrained political objectives; the absence of easy, quick, conventional military options; the implausibility of successful nuclear decapitation ^[3] strategies; the expected horror of actual nuclear conflict.

For a world that seems to be witnessing the formal demise of the Intermediate-range Nuclear Forces Treaty, and—perhaps—the early onset of a post-arms-control era, there’s a measure of comfort to be found in ugly stability. It underlines the fact that nuclear deterrence, at its core, isn’t a carefully-crafted bargain but a swirl of fear and uncertainty about the imminent prospect of large-scale, escalating, and uncapped destruction.

True, the measure of comfort to be found in ugly stability isn’t great. India and Pakistan have made the best of the condition to keep the subcontinent safe for over a quarter of a century. But events over recent weeks ^[4] have helped to underline the fact that the crude lumpiness of nuclear deterrence sometimes makes for difficult signalling. Moreover, context matters. Indian Prime Minister Modi’s in the middle of an election campaign, making bargaining and accommodation even more challenging than usual. His chest-thumping ^[5] after India’s ‘surgical strikes’ in Pakistan-controlled Kashmir in response to an attack on India’s military base in Uri in 2016 made it essential for him to authorise a more robust retaliation after the terrorist attack in Pulwama in February this year. Back then, Islamabad used plausible deniability to refute India’s claims of having entered Pakistan-controlled Kashmir, thereby avoiding the need to respond. This time around, however, Pakistan’s newly-elected prime minister, Imran Khan, had to be seen to be acting, especially given the fact that India had conducted air strikes within undisputed Pakistani territory.

In an age of social media and 24/7 news channels, it’s harder to control messaging—a fact that’s been underlined by recent events. Both India and Pakistan were seeking a way out of the crisis but were boxed in by public expectations and past rhetoric. Ultimately, both fed their own narratives of victory to their citizens and stepped back from their escalation options. The ugliness of the relationship persists—in continuing ceasefire violations ^[6], among other things—but stability prevails.

So we’re not arguing that ugly stability is an ideal condition upon which to base the long-term future of the global nuclear order. Rather, it’s a safety net that adds a layer of security to nuclear balances when the high-wire competitors over-reach. And because of that safety net, we should be less nervous about either a fraying of the rope, or the limited skills of the trapeze artists.

A faltering of arms control does not automatically mean nuclear war is more likely ^[7]. Similarly, an escalating strategic competition between the great powers does not mean that a return to nuclear arms racing, reminiscent of the early days of the Cold War, is inevitable. Even in a world without INF and the Strategic Arms Reduction Treaty, nuclear-armed states are unlikely to see benefit in either nuclear war or arms racing.

The downside of ugly stability is that between safety net and hard ground there are few things that might break any further fall. Domestic political transformation might be one such thing: fans of Tom Clancy’s novel Red Storm Rising ^[8] will remember that a quickening slide towards nuclear war is arrested by a military coup in the Soviet Union. International intervention might be another: a mixture of exhortation and coercive pressure might be sufficient to de-escalate a nuclear conflict.

But even in those conditions—where the nuclear threshold may have been crossed—the most effective barrier to escalation would still be nuclear deterrence itself. Fear and uncertainty, the animating principles of deterrence, rise steeply as the prospects of unconstrained war increase. Therein lies the greatest incentive for war termination.