There is a growing consensus that arms control needs to innovate to survive. Although Russia and the United States have greatly reduced the size of their arsenals, their bilateral arms control agreements increasingly seem like Cold War relics in a second nuclear age.
Moreover, even these arms control agreements are now in jeopardy, as Russia has said it will not agree to further reductions until other nuclear states—most notably, China—join the arms control process. For their own part, nuclear states such as China and India claim that the limited size of their nuclear arsenals requires that they maintain a high degree of secrecy, and they refuse to agree to reductions so long as Russia and the United States maintain about 90 percent of the world’s nuclear weapons.
Fortunately, there is a politically viable arms control agreement that could break the gridlock even as it greatly reduces impending nuclear dangers: The world’s nuclear powers should come together to ban the land-based multiple independently targetable re-entry vehicle (MIRV) that allows ballistic missiles to carry up to 12 small nuclear warheads, each capable of being aimed at a different target.
As seen during the Cold War, MIRVs undermine strategic stability and invite a nuclear arms race. They are destabilizing primarily because they put a premium on striking first. This is true for a number of reasons. First, and most obviously, MIRVs can hit a number of targets with a single missile. Second, MIRVs make it easier for a country to launch multiple warheads at a single target, and multiple small warheads are more destructive than a single larger warhead with an equivalent yield. Third, having multiple re-entry vehicles makes it easier for MIRV missiles to penetrate anti-ballistic missile defense systems.
For all these reasons, MIRV missiles make small- and medium-size nuclear arsenals extremely vulnerable to decapitating first strikes. A rival’s acquisition of a MIRV capability therefore forces nuclear states to greatly expand the size of their arsenals, as well as to further disperse them, to retain a secure second-strike capability. A nation’s own acquisition of MIRV missiles also creates the need to build more nuclear weapons to equip the missiles with multiple warheads.
The United States and Russia have previously attempted to ban MIRVs, beginning with the Strategic Arms Limitation Talks (SALT) that took place between 1969 and 1972. Not comprehending the destabilizing effects MIRVs would have, Henry Kissinger, who was then President Nixon’s National Security Advisor, successfully killed the MIRV ban proposed during the talks. He came to regret it just a few years later, remarking in 1974, “I would say in retrospect that I wish I had thought through the implications of a MIRVed world more thoughtfully in 1969 and 1970 than I did.”
At the beginning of the SALT negotiations, the United States had just begun testing MIRV missiles, and neither side had deployed them. Consequentially, a ban agreed-to early in the talks would not have required onsite inspections, since it could have been verified by monitoring missile tests. Once both sides had deployed MIRVs, however, verifying a ban required onsite inspections, which the Soviet Union refused to allow until the waning days of the Cold War. Later, both countries agreed to a ban on all land-based MIRVs under START II, but this treaty never came into force.
Today the world has another window of opportunity to ban land-based MIRVs. Although the United States and Russia have land-based MIRV missiles, both sides already allow onsite inspections. Meanwhile, both China and India are believed to be actively seeking a MIRV capability but have yet to acquire one. Once Beijing and Delhi have fully tested and deployed MIRV missiles, banning them will be politically impossible since neither side will allow onsite inspections.
The stakes could hardly be higher. If China and India acquire MIRV missiles, both sides are likely to expand the size of their nuclear arsenals exponentially, and to further disperse them. Delhi’s MIRV capability will naturally force Pakistan to expand the size of its arsenal accordingly, and to seek a MIRV capability for itself. The expansion of China’s nuclear arsenal will similarly push Russia to expand its strategic forces as it uses nuclear superiority to offset its growing conventional inferiority. That will put pressure on the United States to increase its nuclear arsenal to retain parity with Russia. Thus, China and India’s acquisition of MIRV missiles will spark a nuclear arms race even as it greatly reduces the strategic stability of nuclear Asia.
Fortunately, an agreement between the United States, Russia, China, India, and Pakistan (and potentially others) to ban land-based MIRVs is possible, but only if all sides move quickly. (China has already tested its DF-31 intercontinental ballistic missile, which is believed to be MIRV-capable, twice.) The United States has every interest in the ban because it has already announced it will phase out land-based MIRV missiles. China, India, and Pakistan all have an interest in banning MIRVs in order to forestall a nuclear arms race that none of them can afford. A MIRV ban would also be in Russia’s interest because it enables Russia to maintain its nuclear superiority over rising states such as China and India.
A ban would also be easy to enforce. Russia and the United States could verify the ban through the onsite inspections they already conduct. Compliance by China, India, and Pakistan could be verified simply by monitoring their missile tests. If all goes well, the ban could be expanded to include MIRV submarine-launched ballistic missiles, with or without France and the United Kingdom.
A MIRV ban is both politically possible and entirely sensible. It would greatly reduce nuclear dangers, forestall a nuclear arms race, and create momentum for further multilateral arms control agreements. In other words, it would finally bring arms control into the 21st century.