Bringing Russia’s New Nuclear Weapons Into New START

Pranay Vaddi
Tuesday, August 13, 2019, 8:00 AM

The last treaty that limits the United States’s and Russia’s nuclear weapons, the New Strategic Arms Reduction Treaty (New START), will expire in February 2021 unless both states agree to its extension. Opponents of extension, including some U.S. officials, have argued against extending the treaty by citing Russia’s new, developmental strategic weapons, which they claim will not be covered by the treaty. Yet the reality is more complex.

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The last treaty that limits the United States’s and Russia’s nuclear weapons, the New Strategic Arms Reduction Treaty (New START), will expire in February 2021 unless both states agree to its extension. Opponents of extension, including some U.S. officials, have argued against extending the treaty by citing Russia’s new, developmental strategic weapons, which they claim will not be covered by the treaty. Yet the reality is more complex. If the Trump administration is serious about limiting the most immediately worrisome of these weapons, New START provides a framework to do so.

New START limits each country to 700 deployed strategic delivery systems—that is, on intercontinental ballistic missiles (ICBMs), sea-launched ballistic missiles (SLBMs) and heavy bombers. On top of that, both countries are allowed up to 800 deployed and nondeployed launchers and heavy bombers. The treaty also limits the number of warheads deployed on strategic delivery systems to 1,550. As of July 1, 2019, Russia possessed 524 deployed delivery systems, 760 deployed and nondeployed launchers and heavy bombers, and 1,461 deployed accountable warheads. Russia is, therefore, legally permitted to build up its deployed strategic forces—but not by much.

Opponents of extension point to President Vladimir Putin’s State of the Nation speech on March 1, 2018, during which he unveiled four “exotic” nuclear-capable strategic weapons: the Avangard hypersonic glide vehicle (HGV), the Kinzhal air-launched ballistic missile (ALBM), the Poseidon (or Status-6) undersea autonomous nuclear delivery vehicle, and the Burevestnik nuclear-powered cruise missile. Poseidon and Burevestnik are unlikely to be deployed during New START’s lifespan, even if it is extended. U.S. intelligence officials believe Poseidon won't be ready until 2027 at the earliest, and tests of Burevestnik have gone poorly so far—seven people were killed last week when a small nuclear reactor believed to be under development for the missile exploded. In any case, they should have little influence on U.S. deterrence strategy in the near term; they should not be major factors in the administration’s consideration of New START extension. By contrast, Russia will likely deploy Avangard and Kinzhal within the treaty’s lifespan, making them pressing topics for U.S. arms control negotiators.

The administration’s interest in ensuring that Russia cannot circumvent the treaty’s limits by introducing new, unconstrained strategic nuclear capabilities is understandable. Through New START, the U.S. government receives a notification when treaty-accountable weapons are produced, when they are deployed, when they are moved (including information regarding to where and for how long), and when they may be tested or used in an exercise. Because all accountable strategic nuclear delivery systems must carry unique identifiers under New START, U.S. inspectors can track the life of each weapon in Russia’s strategic forces from its production to its eventual dismantlement or destruction. Ensuring that Russia’s new strategic weapons are subject to these transparency arrangements would be a great potential benefit to the United States.

The future of New START will depend at least in part on how it can be used to address Avangard and Kinzhal. The treaty offers some options for how to do this, through its clear definitions of the weapons systems to which it applies and the ways it anticipated the development of new strategic offensive armaments. Ultimately, though, integrating Russia’s new developmental weapons will require additional negotiations. Either party can find reasons to be obstinate, but objective analysis highlights a path to limiting these two weapons.


HGVs are epitomized by incredible maneuvering capabilities, entering the Earth’s atmosphere with the speed of a ballistic missile and the aerodynamic flight and maneuvering capabilities of a cruise missile. These attributes make Avangard much harder to target with missile defense interceptors than the ballistic flight path of most strategic nuclear missiles, including the ICBMs and SLBMs accountable in New START. This weapon demonstrates Russia’s clear motivation to develop new offensive weapons to negate any perceived deterrence advantage sought by the United States in developing missile defenses after leaving the ABM Treaty. President Putin is so confident in these capabilities that he has described the Avangard HGV as “invulnerable” to intercept by any existing or prospective missile defense system. But these advanced features also come with increased costs, and Russia reportedly seeks to produce no more than 60 total weapons due to the expensive composite materials required to withstand the temperature of Avangard’s high-speed maneuvering in the atmosphere.

Russia plans to deploy the Avangard HGV on the SS-19 Stiletto and the SS-X-30 Sarmat ICBMs, which are treaty-accountable types of weapons. Therefore, any of the missiles on which Avangard is deployed will be subject to the numerical ceilings and verification provisions of New START. Indeed, a U.S. official confirmed the view that Avangard meets existing treaty definitions, calling it an existing “type” of ICBM, given its planned deployment mode (in this case, the U.S. official appears to be referring to Avangard as the combined HGV-ICBM system).

Separately, the Avangard HGV itself also meets New START’s definition of a reentry vehicle (RV)—that is, an object capable of surviving atmospheric reentry and delivering a weapon to a target, albeit one with unique flight characteristics. Consequently, all deployed Avangard HGVs will be subject to New Start’s overall 1,550 warhead limit and associated verification provisions.


Heavy bombers “equipped to carry nuclear armaments” are subject to New START’s limits. While the aircraft themselves count toward the limits for deployed strategic delivery systems and deployed and nondeployed launchers, the nuclear armaments they carry are not directly accountable. Instead, the treaty uses a “counting rule,” attributing a single warhead, out of the maximum of 1,550, to each deployed nuclear-capable heavy bomber. Two issues are relevant to determining Kinzhal’s accountability under New START: (a) examining whether the missile meets treaty definitions for a nuclear armament, and (b) determining if Kinzhal’s carrying aircraft qualifies as a heavy bomber.

Kinzhal is a nuclear air-to-surface missile, which New START classifies as a type of air-launched nuclear armament. Given the counting rule, any limitation on Kinzhal depends on whether the weapon’s carrying aircraft meets the New START criteria for a heavy bomber. New START defines a heavy bomber as a nuclear-capable bomber that either has an unrefueled range greater than 8,000 kilometers or is equipped for long-range, nuclear-armed air-launched cruise missiles (LRNA). As Kinzhal is not a LRNA—it follows a ballistic trajectory—the analytical focus is on the aircraft’s range.

Russia’s current plan appears to be to deploy Kinzhal on the MiG-31 Foxhound interceptor, which has a range of approximately 1,250 kilometers. In this case, Kinzhal would not be accountable under New START, and neither should it be. Because the MiG-31 has a very limited range, it is not, even when armed with Kinzhal, the kind of strategic weapon that New START was intended to limit. Rather, if Kinzhal is deployed on a MiG-31, it will likely fill a limited, theater-strike role.

However, Russia is also modernizing the Tu-22M3 Backfire medium bomber, which may be used to carry the Kinzhal in the future. There are two scenarios in which the modernized Backfire’s capabilities would create a strong basis for bringing the aircraft and Kinzhal into treaty accountability.

First, it’s possible that the modernized Backfire will meet New START’s heavy bomber definition. The current Backfire has a range of nearly 7,000 kilometers, and the modernization program includes adding fuel-efficient engines to the aircraft, which may add to its range. If its range exceeds 8,000 kilometers and it is used to carry Kinzhal, then the bomber would become accountable under New START.

Second, even if the modernized Backfire’s range capability is less than 8,000 kilometers but it is used to carry Kinzhal, U.S. policymakers may still have a good argument that the aircraft should be limited as a “new kind” of strategic offensive armament under Article V of the treaty. This provision was included so that, if required, the treaty could govern new offensive arms of strategic range that do not meet treaty definitions for existing accountable weapons. The New START Treaty Bilateral Consultative Commission (BCC), the diplomatic commission charged with treaty-related negotiations, is the appropriate forum for examining whether a new weapon is indeed a new kind and whether (and how) to limit it through New START. I am a former member of the U.S. BCC delegation and have engaged in regular implementation discussions in Geneva. If the delegations are empowered by their respective capitals to resolve treaty implementation issues, the BCC has the right interagency experts to conduct technically detailed negotiations.

During Senate ratification hearings in 2010, U.S. officials stated that a “new kind” of strategic offensive armament must be (a) a nuclear-armed weapon with (b) strategic range that is (c) not otherwise treaty accountable. Putin himself acknowledged Kinzhal could be “nuclear-armed” when he described it as capable of delivering nuclear and conventional warheads. Moreover, as an ALBM, Kinzhal would not otherwise be New START accountable. Critically, the missile’s operational range of up to 3,000 kilometers, when combined with the maximum range of even the current Backfire, would give the weapon a total range greater than 8,000 kilometers and allow it to be used against targets in the United States.

Taken together, these criteria would make the Kinzhal-Backfire pairing exactly the kind of strategic weapon that New START was designed to govern and that was anticipated by the language in Article V. It is certainly legitimate for U.S. policymakers to seek limits on Kinzhal. However, to establish the weapon as subject to the treaty, both parties would need to reach an agreement to do so and determine how to apply New START’s verification provisions to the new weapon, carrying aircraft and Backfire airfields—none of which Russia has ever opened for inspection. Reaching such an agreement regarding Kinzhal would require a longer negotiation with Russia than would be the case with Avangard and could involve U.S. concessions. To this point, the administration would likely need to address outstanding Russian concerns about U.S. New START implementation to create a balanced “trade.”

A Starting Point for Negotiations

Trump administration officials have stated a clear interest in limiting Russia’s new “exotic” strategic weapons—and they have a path to do so in the case of weapons that might plausibly be deployed during the lifetime of New START, even if it is extended. U.S. policymakers should, therefore, bring up these weapons during the new U.S.-Russia strategic security dialogue agreed to in Sochi, the first session of which occurred on July 17.

In negotiations, the U.S. delegation should prioritize the following objectives:

  1. Codify Avangard as New START accountable: The United States should confirm with Russia that Avangard meets existing treaty definitions and direct experts to negotiate the application of the verification provisions to the weapon in the BCC, including how the weapon may be presented to inspectors during an ICBM front-section inspection.
  2. New Kinds Transparency: The United States should seek regular updates from Russia, through the Nuclear Risk Reduction Centers, on tests, production and deployment to operational bases of the new strategic weapons (mimicking existing New START notification requirements for ICBMs and SLBMs). This would provide some confidence to U.S. policymakers that they would not be caught by surprise by developments in Russian strategic weaponry while they consider New START extension or replacement. In return, the United States should agree to provide notifications to Russia of any strategic weapons systems that would not be New START accountable that it may pursue in the future.

Separately, the United States should state its red lines on Kinzhal. The United States should make a unilateral statement that it will consider Backfire subject to New START’s limits as a heavy bomber if Russia tests Kinzhal on the aircraft. This should signal to Russia that deployment of Kinzhal on Backfire will change U.S. thinking on the weapon’s purpose and New START accountability, and potentially raise compliance or at least circumvention concerns. This could motivate negotiations to address Kinzhal within New START.

U.S. officials who support extending New START can clear a tall hurdle if they use the ample legal grounds that the treaty provides to limit Avangard and possibly Kinzhal through the ongoing strategic security dialogue with Russia. The only alternative way to limit these weapons would be to negotiate a new treaty—an endeavor with a high chance of failure. Ultimately, extending New START is the best option for dealing with the most immediately worrisome of Russia’s new strategic weapons.

Pranay Vaddi is a fellow with the Nuclear Policy Program at the Carnegie Endowment for International Peace. He holds a J.D. from the University of Pittsburgh.

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