Tactical nuclear weapons, 2019

One of the most dramatic effects of the end of the Cold War was that nonstrategic or short-range tactical nuclear weapons faded into the background of military and political planning and rhetoric. Although many were retained, tactical nuclear weapons generally were first on the chopping block when US President George W.H. Bush and Russia’s leader, Mikhail Gorbachev, initiated sweeping unilateral and reciprocal nuclear arms reduction initiatives in the early-1990s. As a result, the combined number of tactical nuclear weapons in the US and Russian arsenals have declined dramatically by an order of magnitude from 20,000–30,000 in the late-1980s to less than 2,500 today (see Table 1).

The change has been most dramatic in the US arsenal, which saw the complete elimination of tactical nuclear weapons from the Army, Marine Corps, and Navy. Almost all nuclear weapons were withdrawn from overseas locations, and the entire surface fleet was denuclearized. The overall inventory declined from approximately 9,000 weapons in 1989 to about 230 today, all of which are bombs for tactical fighter aircraft. Although strongly motivated by the geopolitical changes in the former Soviet Union and Eastern Europe, this development was also precipitated by practical military considerations. Even before the Cold War ended, the military had already started phasing out several types of tactical nuclear weapons because they were no longer needed; increasingly efficient conventional weapons could do the job. Destruction of some complex targets still required nuclear weapons that continued to serve to deter adversaries and reassure allies, but those roles could be largely performed by strategic weapons.

The Russian reduction of tactical nuclear weapons has been equally dramatic in terms of numbers, which have declined from 13,000–22,000 in the late-1980s to less than 2,000 today. All the major military services continue to have tactical nuclear weapons. The Russian military has held on to more tactical nuclear weapons than the US military, predominantly to offset the effect of more advanced and efficient US conventional forces and to some extent Chinese conventional forces (although US capabilities appear to be the main factor). As a result, Russian nuclear strategy relies more on tactical nuclear weapons, some of which potentially could be used if Russia was losing a conventional war with NATO. Moreover, the large inventory of tactical nuclear weapons allows Russia to keep overall nuclear parity with the combined forces of the United States, France, and Britain.

Among the other nuclear-armed states, France and Britain have eliminated their inventories of tactical nuclear weapons, although French air-launched weapons have characteristics that are similar to those of some Russian tactical nuclear weapons. Pakistan is fielding explicitly tactical nuclear weapons, and its arsenal includes several other types of nuclear weapons that would be considered tactical if they were part of the Russian or US arsenals. That is also the case for China, India, Israel, and North Korea.

For the first two decades after the end of the Cold War, the role of and disparity of US and Russian tactical nuclear weapons didn’t matter much. But after relations soured, Russia invaded Ukraine and issued nuclear threats against NATO countries, and the Trump administration proclaimed the reemergence of great power competition, tactical nuclear weapons have made a worrisome comeback. Both sides are modernizing their tactical nuclear arsenals, adding new types to the inventory and increasing the role and salience of tactical nuclear weapons in their military strategies. Moreover, tactical nuclear weapons are being used to threaten existing arms control agreements, including the INF treaty, which was killed by a dispute over a new Russian intermediate-range missile and references to Chinese weapons, and the New START treaty, the extension of which is being threatened partly by demands that arms control must be expanded to include tactical nuclear weapons.

This double-edged sword of undermining existing limits on nuclear arsenals and increasing tactical nuclear weapons threatens to recreate some of the dynamics that during the Cold War triggered an arms race and dangerous escalation strategies that increased the risk of nuclear war.

Definitions

Before we describe the tactical nuclear arsenals, it is important to review what a tactical nuclear weapon actually is. Unlike other types of nuclear weapons and associated delivery systems, there is no universally-accepted definition for a “tactical,” “nonstrategic,” or “theater” nuclear weapon. During the Cold War, such weapons were also referred to as “battlefield” nuclear weapons.

According to the US Defense Department’s publication Nuclear Matters Handbook, “Non-strategic or tactical nuclear weapons refer to nuclear weapons designed to be used on a battlefield in military situations. This is opposed to strategic nuclear weapons, which are designed to be used against enemy cities, factories, and other larger-area targets to damage the enemy’s ability to wage war” (Department of Defense 2016, 17).

The Joint Chiefs of Staff’s dictionary of military terms from 2010 defined nonstrategic nuclear forces: “Those nuclear-capable forces located in an operational area with a capability to employ nuclear weapons by land, sea, or air forces against opposing forces, supporting installations, or facilities. Such forces may be employed, when authorized by competent authority, to support operations that contribute to the accomplishment of the commander’s mission within the theater of operations” (Joint Chiefs of Staff 2010, 331). The updated version from 2019, however, does not mention nonstrategic nuclear weapons at all (Joint Chiefs of Staff 2019a).

A frequent and widespread mistake in the public debate is to equate nonstrategic with low yield. If a weapon has a low-yield option, so the thinking goes, then it’s a nonstrategic weapon; conversely, if it has a high yield, then it must be a strategic weapon. The reality is much more blurred and complex; some nonstrategic nuclear weapons have high-yield options, some strategic weapons have low-yield options; some have both.

A more official distinction is the arms control definition, according to which everything not formally designated as a “strategic nuclear weapon” by strategic arms limitation treaties is de facto a “nonstrategic” nuclear weapon. Key to this definition is range: strategic weapons have intercontinental range, nonstrategic weapons do not. This is of course a very superpower-dominated definition that ignores the characteristics and histories of other countries’ nuclear arsenals, some of which don’t even include intercontinental-range weapons.

Yet the arms treaty definition does capture the relation to the military mission and the very different consequences of strategic versus nonstrategic use. Strategic missions are immensely more destructive because of their scope and intensity, while tactical missions are nominally intended for limited regional scenarios. The Congressional Research Service has stated that the true marker of a tactical nuclear weapon could be “the nature of the target or implications for the conflict, not the yield or delivery vehicle of the attacking warhead” (Congressional Research Service 2019, 10).

Even so, the distinction between a strategic and nonstrategic nuclear weapon or mission is inherently fuzzy and will probably remain so, given that strategic nuclear weapons can be used in a tactical manner and that any use of a nuclear weapon, no matter how small the yield or short the range, would have far-reaching strategic consequences. This sentiment was echoed by former Secretary of Defense James Mattis in February 2018, when he testified in front of the House Armed Services Committee that he does not believe that “there is any such thing as a tactical nuclear weapon. Any nuclear weapon used any time is a strategic game changer” (Mattis 2018).

Russian tactical nuclear weapons

The Russian government does not provide public overviews of its tactical nuclear weapons, identify which tactical launchers are nuclear-capable (although officials will sometimes claim a new system is nuclear), or say how many it has. The closest we have to a numerical declaration is a statement initially made by then-Deputy Foreign Minister Sergey Kislyak (and later ambassador to the United States) to the 2005 NPT Review Conference, that Russia’s “non-strategic nuclear forces” had been reduced “by four times” since 1991, to one-quarter of the inventory back then (TASS 2005). But since Russia never disclosed how many nonstrategic nuclear weapons it had in 1991, Kislyak’s declaration left everybody guessing. Moreover, the exact same declaration was repeated five years later at the 2010 NPT Review Conference (Russian Federation 2010, 8), which implied that no additional reductions were made between 2005 and 2010 (an implication that seems unlikely to be true). If Russia had 13,000–22,000 tactical weapons in 1991, then a “four times” reduction would have left 3,250 to 5,500 weapons. That appears to be close to the estimate used in 2009 by then-Principal Deputy Undersecretary of Defense for Policy James Miller when he informed NATO allies that Russia’s arsenal included 3,000–5,000 “sub-strategic nuclear weapons” (USNATO 2009).

Over the past decade, this arsenal has further decreased significantly (that is, by 1,000–3,000 weapons), to “up to 2,000 non-strategic nuclear weapons,” according to the 2018 Nuclear Posture Review (Department of Defense 2018, 53). This decrease contradicts the claim made elsewhere in the NPR that “Russia’s non-strategic nuclear weapons modernization is increasing the total number of such weapons in its arsenal” (Department of Defense 2018, 9). US officials privately say the number did increase some in 2016, but hasn’t done so since (Kristensen 2019).

Some officials responsible for advocating modernization of US nuclear weapons have even suggested Russia might have more than “up to 2,000” tactical nuclear weapons. Some say “approximately 2,000” (Lord 2019, 3), which implies around 2,000, or even 2,500 (Dunford 2019). (Joint Chiefs of Staff Chairman Joseph Dunford’s office later corrected his statement and referred to the NPR estimate (Ryder 2019).)

Estimates are difficult to make, and they always come with considerable uncertainty. They are, as the word says, estimates and not actual, official numbers. Uncertainty, unknowns, and confusion mean estimates can only be approximate. Moreover, they will reflect the capability and culture of those who produce them, and there is disagreement within the US intelligence community about how many tactical nuclear weapons Russia has. Part of the disagreement reflects differing analysis of an objective reality: Russia has indeed increased the number of delivery platforms that could potentially launch tactical nuclear weapons. But this does not necessarily mean that the total number of warheads has also increased. US government officials have privately explained it in this way: Just because there are more launchers of a system that has nuclear capability doesn’t necessarily mean there are also more warheads assigned to that category of launchers (Kristensen 2019). Most of the new systems are dual-capable and many of the launchers of those systems may not be assigned a nuclear role at all; instead, they might be focused on the conventional mission. So simply adding up nuclear-capable launchers across the system or category could produce an inflated estimate of the warhead inventory.

Whatever the actual number of Russian tactical warheads is, it has not increased over the past decade. Looking to the future, however, the US Defense Intelligence Agency (DIA) in 2019 projected that Russia’s “overall nuclear stockpile is likely to grow significantly … primarily driven by a significant projected increase in the number of Russia’s nonstrategic nuclear weapons” (Ashley 2019). It should be pointed out, however, that this is DIA’s projection and not a coordinated assessment by the Director of National Intelligence. Moreover, past DIA projections have been inaccurate (Kristensen 2019a).

Another uncertainty involves the types of launchers that can fire tactical nuclear weapons. During the Cold War, there was an abundance of official documents and statements that gave details about Soviet nuclear forces. When the Cold War ended, these sources largely dried up, and for the next two decades the US government did not publish overviews and largely avoided making public statements about the size and composition of Russia’s nuclear arsenal. Since the 2017 National Security Strategy embraced great power competition (White House 2017, 27); however, several new publications and official statements have provided details again.

The NPR itself states that Russian nonstrategic nuclear weapons include “those employable by ships, planes, and ground forces. These include air-to-surface missiles, short range ballistic missiles, gravity bombs, and depth charges for medium-range bombers, tactical bombers, and naval aviation, as well as anti-ship, anti-submarine, and anti-aircraft missiles and torpedoes for surface ships and submarines, a nuclear ground-launched cruise missile in violation of the 1987 INF Treaty, and Moscow’s antiballistic missile system” (Department of Defense 2018, 53).

It is unclear if there are more types of systems. We are aware that STRATCOM has given Congress at least one briefing on Russia’s non-strategic nuclear forces that listed some launchers that the intelligence community does not consider to be nuclear. Likewise, during testimony to Congress in 2019, US Under Secretary of Defense for Acquisition and Sustainment Ellen M. Lord added two weapon systems to the NPR’s list of Russian tactical nuclear weapons: landmines and artillery shells (Lord 2019).

Given such uncertainties and confusion (plus those added by non-official rumors from private institutes and news media reports), creating an unclassified overview of Russian nonstrategic nuclear weapons comes with considerable uncertainty. As best as we can assess, Russia might have roughly 1,830 nuclear warheads for delivery by launchers that are considered nonstrategic or tactical. All of those launchers are dual-capable, which means they can be used for both conventional and nuclear missions (Kristensen and Korda 2019).

US tactical nuclear weapons

Like Russia, the United States does not disclose how many tactical nuclear weapons it has or where they are deployed. But it does provide information about which weapons types are capable of launching them. Since the end of the Cold War, the US inventory of tactical nuclear weapons has decreased significantly, from roughly 9,000 warheads in 1989 (SIPRI 1989, 13) to an estimated 230 today. The 2018 Nuclear Posture Review provides this information about US tactical nuclear weapons:

Most of the estimated 230 remaining weapons – about 150 B61-3 and −4 gravity bombs – are thought to be deployed at six bases in five European countries: Aviano AB and Ghedi AB in Italy; Büchel AB in Germany; Incirlik AB in Turkey; Kleine Brogel AB in Belgium; and Volkel AB in the Netherlands. A portion of the B61 bombs in Europe are earmarked for delivery by aircraft from the NATO allies where the bombs are stored. The remaining 80 weapons are in central storage in the United States (Kristensen 2017). The number in Europe is thought to have been quietly reduced (from 180) over the past decade because of upgrades to the security perimeters and storage vaults at Aviano AB and Incirlik AB (Kristensen 2015).

NATO is currently in the middle of an upgrade of the nuclear weapons storage facilities and command and control equipment at the six European storage bases and one support base. The upgrade is expected to be completed in 2020, in time for the deployment of the new B61-12 nuclear bomb to Europe.

US modernization of its tactical nuclear weapons is focused on production of the B61-12 guided nuclear bomb and the F-35A Lightning fifth-generation fighter-bomber. The B61-12 will use the nuclear explosive package of the existing B61-4, which has four selective yields between 0.3 kilotons and 50 kilotons, but it will be equipped with a new guided tail kit to increase accuracy and standoff capability. This will allow strike planners to select lower yields for existing targets to reduce collateral damage. The enhanced accuracy will enable the B61-12 to serve the missions of all nuclear gravity bombs in the arsenal and allow the Air Force to retire all existing bombs, although the Trump administration has delayed retirement of one of these, the B83-1. Production of the first B61-12 is expected in March 2020, although it might be delayed because of production problems for some components. Several NATO countries are upgrading their current dual-capable F-16 or Tornado fighters to the F-35A.

The B61-12 also appears to have some limited earth-penetration capability, which increases its ability to hold at risk underground targets (Kristensen and McKinzie 2016). The B61-12 will be deployed to Europe beginning in 2022–2024, at which point the older B61-3 and B61-4 bombs will be returned to the United States.

Although many have questioned the continued need to forward-deploy US nuclear weapons, the United States and NATO have retained the mission as a symbol of US protection of NATO. This role has deepened in recent years as relations with Russia have soured, and the United States and NATO have reemphasized the role of nuclear weapons in support of the alliance. Although the nuclear sharing arrangement is limited to five countries, allies who do not host US nuclear weapons on their soil can also participate in the nuclear mission as part of conventional support operations, known as SNOWCAT (Support Nuclear Operations With Conventional Air Tactics).

Although the United States has been emphasizing the continued importance of deploying tactical nuclear weapons in Europe, the 2018 Nuclear Posture Review determined they were insufficient to deter Russian use of tactical nuclear weapons there. New nuclear “supplements” were needed: a low-yield warhead for the Trident II D5LE submarine-launched ballistic missile (SLBM) and a new nuclear sea-launched cruise missile (SLCM) explicitly for the purpose of “enhancing deterrence with non-strategic nuclear capabilities” (Department of Defense 2018, XI).

“Unlike (dual-capable aircraft),” the NPR explained, “a low-yield SLBM warhead and SLCM will not require or rely on host nation support to provide deterrent effect. They will provide additional diversity in platforms, range, and survivability, and a valuable hedge against future nuclear ‘break out’ scenarios.” The low-yield warhead, known as W76-2, is needed to “ensure a prompt response option that is able to penetrate adversary defenses.” The SLCM is needed to “provide a needed non-strategic regional presence, an assured response capability. It also will provide an arms control compliant response to Russia’s non-compliance with the Intermediate-range Nuclear Forces Treaty, its non-strategic nuclear arsenal, and its other destabilizing behaviors.” The new weapons will “provide a diverse set of characteristics enhancing our ability to tailor deterrence and assurance” and “expand the range of credible U.S. options for responding to nuclear or non-nuclear strategic attack” (Department of Defense 2018, XII-XIII).

The idea to deploy a low-yield W76-2 warhead on strategic Trident submarines for potential use as a quick-strike tactical nuclear weapon early in a conflict appears to blur the line between tactical and strategic nuclear weapons. Moreover, given that the US Navy already has high-yield warheads on its Trident warheads that could be used in a response, the decision to add a low-yield warhead suggests an interest in being able to use the new weapon more readily because it would create less radioactive fallout.

The new weapons are needed, the NPR claims, to “help counter any mistaken perception of an exploitable ‘gap’ in US regional deterrence capabilities.” There is no evidence that Russia doubts US resolve to retaliate if attacked, or that Moscow believes the United States would be “self-deterred” from retaliating if it doesn’t have these new low-yield tactical weapons. Russian planners are likely aware that the US arsenal already includes around 1,000 gravity bombs and air-launched cruise missiles with low-yield warhead options (Kristensen 2017a), and that roughly 150 of those are already deployed in Europe.

The Trump administration’s efforts to revitalize the role of tactical nuclear weapons in US military strategy coincides with the brief publication in June 2019 of a new Joint Chiefs of Staff nuclear weapons doctrine that appeared to emphasize the battlefield use of nuclear weapons (Aftergood 2019):

The limited use of tactical nuclear weapons to “restore strategic stability” is essentially the same concept as the “escalate-to-deescalate” doctrine that the NPR attributes to Russia.

Pakistani tactical nuclear weapons

Pakistan is unique among the smaller nuclear-armed states because it the only one that has explicitly and publicly embarked on a program to develop tactical nuclear weapons. The decision is largely a reaction to India’s so-called Cold Start doctrine, which establishes the capability to rapidly launch retaliatory, large-scale, conventional strikes against Pakistani forces and territory–at a scale below Pakistan’s nuclear threshold. Because Pakistan believed it lacked the conventional forces capable of repelling such an Indian attack, it decided it needed tactical nuclear weapons.

As General Khalid Kidwai, a retired member of Pakistan’s National Command Authority, stated at the 2015 Carnegie International Nuclear Policy Conference, “This was a Pakistani defensive, deterrence response to an offensive doctrine.” He continued: “I strongly believe that by introducing the variety of tactical nuclear weapons in Pakistan’s inventory […], we have blocked the avenues for serious military operations by the other side” (Kidwai 2015, 4–5).

The cornerstone of Pakistan’s tactical nuclear arsenal is the NASR (Hatf-9) short-range ballistic missile–a short-range, solid-fuel missile originally with a range of only 60 kilometers (37 miles) that has recently been extended to 70 kilometers (43 miles). With a range too short to attack strategic targets inside India, the Nasr appears to solely be intended for battlefield use against invading Indian troops and tanks. According to the Pakistani government, the NASR “carries nuclear warheads of appropriate yield with high accuracy, shoot and scoot attributes” and was developed as a “quick response system” to “add deterrence value” to Pakistan’s strategic weapons development program “at shorter ranges” in order “to deter evolving threats” (ISPR 2011, 2017).

The four-axle, road-mobile transporter erector launcher (TEL) for the NASR appears to use a snap-on system that can carry two or more launch-tube boxes. The system has been tested in the past using a road-mobile quadruple box launcher. The US intelligence community has listed the NASR as a deployed system since 2013, and with a total of 15 tests reported so far, the weapon system appears to be well-developed. Potential deployment locations include Army garrisons in Gujranwala, Okara, and Pano Aqil (Kristensen 2016).

In addition to the NASR, Pakistan also maintains a stockpile of other nuclear-capable missiles that have characteristics similar to what could be considered tactical. This includes short-range ballistic missiles like the Hatf-2 (Abdali) and Hatf-3 (Ghaznavi), Hatf-7 (Babur) ground-launched cruise missile, and Hatf-8 (Ra’ad) air-launched cruise missile, all of which could be used to target India’s conventional forces on the battlefield. However, given the relatively small size of the Pakistani nuclear arsenal, it would likely need to use up an estimated 60 percent of its nuclear stockpile in order to disable a large-scale Indian advance of 1,000 tanks (Nayyar and Mian 2010, 9).

Other countries

Several other nuclear-armed states possess nuclear weapon types that, if they were part of the Russian and US arsenals, would be called tactical nuclear weapons. Due to national terminology, nuclear doctrine, and the history of the evolution of their arsenals, however, these countries do not call their weapons tactical but insist they are all strategic.

China does not describe any of its nuclear forces as tactical weapons. In the 1980s, part of the US intelligence community believed China had or was developing tactical nuclear weapons, including short-range ballistic missiles and nuclear mines (DIA 1984, 4). A US Defense Intelligence Agency estimate of China’s nuclear strategy in 1985 found “there are indications that the Chinese, having recognized [their lack of tactical and theater options below the strategic level] as a weakness in their strategy, are pursuing a variety of programs aimed at developing shorter-range ballistic missiles and other tactical systems more suited to battlefield use. When they reach fruition in the 1990s, such systems may have a major impact on Chinese strategy, particularly employment plans” (Defense Intelligence Agency 1985, 9). Moreover, the CIA believed some of China’s nuclear tests in the early-1990s were related to warheads for short-range ballistic missiles, cruise missiles, and artillery (Norris and Kristensen 2008). Such tactical nuclear weapons do not seem to have been fielded, however, and the Chinese instead appear to have mainly chosen to rely on non-nuclear missiles for tactical use.

Today, “nuclear” is generally thought to be synonymous with “strategic” in Chinese terminology. Nonetheless, most of China’s nuclear-capable missiles do not have strategic range but regional range. This includes the DF-21 medium-range ballistic missile (MRBM) and the DF-26 intermediate-range ballistic missile (IRBM) that potentially could be used in limited options before resorting to the use of ICBMs. In fact, a US Department of Defense fact sheet published with the 2018 Nuclear Posture Review explicitly characterized the DF-21 and DF-26 as nonstrategic weapons: “China is also expanding and modernizing its non-strategic nuclear weapons, including the CSS-5 Mod 6 and DF-26, intended to threaten its neighbors and challenge the U.S.’s ability to conduct regional operations” (emphasis added) (Department of Defense 2018a). According to the Nuclear Posture Review, the US military planners are working on “increasing the range of graduated nuclear response options available to the president” to “strengthen the credibility of our deterrence strategy and improve our capability to respond effectively to Chinese limited nuclear use if deterrence were to fail” (Department of Defense 2018, 32). So while China may not officially have tactical nuclear weapons, the United States military is planning as if it does.

France describes all of its nuclear weapons as strategic, even the short-range ASMPA air-launched cruise missile, which, if fielded by Russia or the United States, would be described as a tactical nuclear weapon. Its range of a little over 500 kilometers and the short-range fighter-bombers that are assigned to deliver it all have characteristics that place the ASMPA in the tactical weapons category – except it is considered to be strategic by France.

Several of India’s nuclear weapons systems also have characteristics that appear tactical, but the Indian government considers them all to be strategic weapons. This includes the Air Force’s fighter-bombers, the Army’s Prithvi-II short-range ballistic missile, and the Navy’s Dhanush missile. The same could be said for some Israeli and North Korean nuclear weapon systems.

Disclosure statement

No potential conflict of interest was reported by the authors.