For four years now, STRATCOM has hosted an annual deterrence symposium that provides opportunities for younger officers and their seniors to hear old hands, U.S. government officials, foreign perspectives, policy influentials, and the occasional heretic. As a networking and learning experience on all matters relating to deterrence, it doesn’t get much better than this.

I was on a panel this year with Frank Miller and George Perkovich addressing the question of whether nuclear weapons are becoming more or less influential in the emerging international security environment. Peter Lavoy, the Pentagon’s Principal Assistant Secretary of Defense for Asia and the Pacific, served as moderator. Videos of the panel discussions and speakers will be posted on STRATCOM’s event web site. [Update: videos have been posted here.] A common answer to hard questions throughout the two-day event, held on August 8-9, was “it depends.” My presentation follows.

Appearances matter. Appearances matter for deterrence. But in all matters other than cosmetic surgery, the force of gravity trumps appearances. Gravity is having its way with the U.S. nuclear stockpile and deployed forces. The effects of gravity are reinforced by budgetary woes and significant trends, including the absence of actual battlefield use and the use of threats to use nuclear weapons. The former is now 67 years old as of this very week. The latter has mostly become the province of outlier states. Responsible states don’t threaten nuclear weapons’ use; irresponsible states do. Numbers matter, but norms matter more. Numbers become a way to reinforce norms. Numbers as well as norms point to the diminished utility of nuclear weapons for the United States. The question before us is whether to assist or resist gravity.

The concept and practice of deterrence are as important as ever. The constituent elements of deterrence are familiar, but the mix is shifting. The use of economic instruments in deterrence equations is growing among four of the P-5, if not all five. Two other elements – space and cyber – are also gaining prominence.

The element of nuclear deterrence has variable salience, depending on individual cases. Every case is unique and hard to categorize. But for purposes of discussion, and to spark rebuttals, I propose the following typology:

1. States with strong conventional forces and significant economic equities, in a global or a regional sense. In these cases, states try to reduce the salience of nuclear weapons in deterrence equations. I place the United States, India, and perhaps Israel in this category.

2. States with multiple weaknesses – military (relative to potential foes), economic, political, and institutional – that have worrisome security challenges. In these cases, the salience of nuclear weapons in deterrence strategies is increasing. Nuclear weapons provide a porcupine defensive strategy, while compensating for worrisome internal and external trends. In this group I would place Pakistan, the DPRK, and Russia.

3. States for whom nuclear weapons are primarily a refection of Cold War history. In these cases, nuclear weapons have a very limited role in deterrence strategies, even though they cost a great deal. Government leaders have difficulty acknowledging this. In this category I would place Great Britain and France.

4. The wild card category: China, a state with a growing economy, rising status and worrisome internal prospects. China has previously demonstrated relaxed requirements for nuclear deterrence, even when Beijing was on poor terms with two superpowers. China’s strategic modernization program continues, but at a modest pace. Beijing’s strategy for achieving great power status has been about economics, not nuclear weapons. Will Beijing become increasingly attached to the Bomb as it becomes better off?

All of these cases, with the exception of Great Britain and France, have important qualifiers.

Israel’s public silence and private reliance on nuclear weapons could be reconfigured in the event that the Iranian nuclear program continues to advance.

India is a status-conscious society with risk-averse leadership that largely views nuclear weapons as political instruments. Consequently, it has a poorly operationalized deterrent. India has done well for itself by trying to reduce the salience of nuclear weapons in deterrence equations, but how long will this continue to be the case, if Pakistan and China take nuclear weapons more seriously?

Pakistan is increasing the salience of nuclear weapons in its deterrence calculations more than any other state. Pakistan’s high-low deterrence mix – nuclear weapons and proxy groups – is deeply problematic. This mix speaks volumes about the severity of the challenges Pakistan faces and how much autonomy Pakistan’s military enjoys.

North Korea is a black box. Surprises are inside. Some might even be positive.

Russia is increasing the salience of its nuclear deterrent even though its external threats are, by historical standards, very modest.

Trend lines that reduce the salience of nuclear weapons in the United States are now a quarter-century old and very well defined. It will take very serious shocks to reverse these trend lines. The shock of 9/11 certainly didn’t.

How does all of this net out?

The economic element of deterrence is growing as the nuclear element is declining, with prominent exceptions. Sanctions have come a long way – to the point where they can even hurt a big oil producer like Iran. They may not deter or compel Tehran, but these sanctions could be an object lesson for potential fence-sitters.

One definition of deterrence is what the competition worries about. We in the United States worry more about China’s economic clout than its nuclear arsenal. Even the Kremlin, with its reflexive, atavistic tendencies toward nuclear and BMD issues, gets more mileage out of threats to turn off pipelines than to vaporize cities.

Can those who now seek increased salience for nuclear deterrence — the outliers and Russia – tip the scales? Not yet. When outliers seek more nuclear weapons, they gain more notoriety, not power. And nuclear weapons are a very poor substitute for what ails Russia. The top line indicators of reduced salience remain strong. The two biggest nuclear stockpiles and deployed force levels are shrinking, and the absence of nuclear testing further reduces the salience of nuclear weapons. If the DPRK tests another nuclear device, it will not gain power, influence, or foreign aid. No one seems to be lining up behind North Korea.

Will nuclear weapons become more or less influential in the emerging international security environment? Given this mixed picture, it depends. It depends mostly on China and whether the Iranian nuclear program will have cascade effects.