The MIRV represents the culmination of a certain Cold War logic: the notion that security can be found in fielding such an overwhelming force that retaliation becomes mathematically inevitable.
The “Multiple Independently Targetable Reentry Vehicle,” or MIRV, is a tool that has revolutionized missile design around the world—effectively making it all but impossible for any nation to prevent a nuclear attack on its home soil.
Put simply, a MIRV allows a single intercontinental ballistic missile (ICBM) or submarine-launched ballistic missile (SLBM) to carry several nuclear warheads on one missile. Once the missile begins its terminal phase toward the target, each warhead can break off and independently target separate locations, severely undermining a nation’s air defense efforts. Of course, this is a deeply consequential development in nuclear weapons technology, in which even one hit among several misses would be cataclysmic for the nation being targeted.
Because each of the MIRV’s warheads can be directed towards different, individual targets, defending against the MIRV system can become complicated quickly. Before the MIRV system existed, a single missile resulted in one explosive yield. By contrast, MIRV has created the potential for an exponential leap in destruction—a single weapon capable of devastating multiple cities at the same time.
Why MIRV Matters for Nuclear Defense
The implications of the MIRV are profound. From a strategic standpoint, MIRVs have fully shifted the calculus of nuclear deterrence in favor of an attacker.
In the early days of the nuclear age, one missile carried one warhead, and while anti-missile defenses were still relatively rudimentary, the challenge of shooting down an enemy missile was still relatively straightforward. Over time, most major powers developed countermeasures to enemy missiles, such as America’s THAAD system and Russia’s S-500—both of which can intercept an ICBM with relatively good accuracy.
But MIRVs, each capable of carrying 10 or more reentry vehicles, make such defense schemes far more complicated. Their impact is especially potent when considering that each MIRV is likely to be accompanied by decoy missiles and other penetration aids. With MIRV missiles, the cost of intercepting an incoming barrage comes to vastly exceed the cost of launching it, making for an asymmetry between offense and defense that eventually erodes the viability of missile defense systems, pushing adversaries instead towards deterrence systems that are reliant upon fear rather than denial.
MIRVs also complicate arms control efforts. Throughout the Cold War, the United States and the Soviet Union first sought to produce more missiles than each other, then to achieve parity through negotiations. But today, if an international treaty caps a nation’s number of delivery systems, that nation can merely equip its existing missiles with MIRV, multiplying its warhead count without building a single new launcher—thereby sidestepping the treaty.
MIRVs Are the Most Destructive Weapons of All Time
With this in mind, it should come as no surprise that both Washington and Moscow invested heavily in MIRVs during the latter stage of the Cold War, causing a dramatic increase in warheads deployed worldwide. The result was instability in the bipolar world order, within which each side recognized increased incentive for launching a first strike. After all, MIRVs could be used to preemptively attack and eliminate an adversary’s missile fields, potentially including the enemy’s MIRVs, before they were launched and became nearly impossible to defend against.
The emergence of MIRVs forced nations to rethink their survival strategy. ICBM silos were hardened and dispersed, to avoid becoming too tempting a target. Simultaneously, submarines were invested in, an alternative to land-based missiles that MIRVs simply could not target. And, when the submarines themselves were loaded with MIRVs, the submarine became a virtually invulnerable tool for retaliation.
The MIRV, which came to be a prestige signal of technological and fiscal prowess, represents the culmination of a certain Cold War logic: the notion that security can be found in fielding such an overwhelming force that retaliation becomes mathematically inevitable. The logic isn’t perfect, though; MIRV proliferation accelerates arms races while sowing seeds of mistrust.
Therein lies the paradox. In a certain respect, MIRVs deter war; in another respect, they invite war, if war can be conducted on favorable terms. The same could be said of nuclear weapons more generally, which remain one of human kind’s true existential threats—especially so when MIRV technology allows for a single missile to raze vast swaths of the planet.
About the Author: Harrison Kass
Harrison Kass is a senior defense and national security writer at The National Interest. Kass is an attorney and former political candidate who joined the US Air Force as a pilot trainee before being medically discharged. He focuses on military strategy, aerospace, and global security affairs. He holds a JD from the University of Oregon and a master’s in Global Journalism and International Relations from NYU.
Image: Shutterstock / ID1974.
