The Pentagon’s annual
on Chinese military power describes for the first time a Chinese nuclear missile with “multiple independently-targetable re-entry vehicles,” or MIRVs. For the uninitiated, that’s the ability to put multiple warheads on a single missile and deliver them separately against targets.
The Federation of American Scientists’ Hans Kristensen
the passage in early May and, just last weekend, David Sanger and William J. Broad
a piece in the
New York Times that includes quotes by several experts, including yours truly. (I have written two books on China’s nuclear posture:
in 2006 and
in 2014. So I guess I should say something about what it means.)
There are two big questions being asked. Does this mean China is changing its nuclear posture? And is this a response to U.S. missile defense programs?
U.S. officials have long expected China to place multiple warheads on the DF-5. My best guess is that the decision to put multiple warheads is about replacing the vintage 1970s warhead on the DF-5 with something more contemporary. This decision was probably made a long time ago, and perhaps it has simply taken Beijing a while to get around to it.
Technical explanations can be a little boring — guess why people opt for the strategic ones? — but let me try. China has a fairly small arsenal of nuclear-armed ballistic weapons, involving two “series” of missiles: one liquid-fueled and solid-fueled. Starting in the early 1960s, China developed the Dongfeng (DF) series of liquid-fueled ballistic missiles — the DF-3, DF-3, DF-4, and DF-5. Liquid fuel is very energetic (which means the missile can fly really far) but it is also super corrosive, thus one can only fuel such a missile right before launch. The drawback is obvious: Imagine stopping to gas up your car while the United States Air Force is doing its utmost to kill you. (Note: All this is pretty simplified — if you really want painful detail, there is a chapter in
Paper Tigers that deals with fascinating questions like: Why did China call two different missiles the DF-3? And why does the United States call the DF-3 the CSS-2?)
Starting in the mid-1980s, China began developing a series of solid-fueled missiles to replace the liquid-fueled ones — the DF-21, DF-31, DF-31A and, in due course, the DF-41. The upside to solid-fuel is that it’s more stable and manufactured into the missile, making it easily transportable. The downside is that the missile it is harder to make and the fuel isn’t as powerful.
China has still not completely replaced the first series of liquid-fueled missiles with the second series of solid-fueled ones. China’s liquid-fueled DF-5 is the only missile that can reach all of the United States — and it has 18 of these bad boys. It deployed most of the first batch in the late 1980s and early 1990s, and then replaced them with a more modern variant in the mid-2000s.
China has an intercontinental ballistic missile (ICBM) in the second series, the DF-31A, that can reach targets across much of the United States, but I have some questions about just how much of the United States. Not surprisingly, China is developing something new: a missile designated the DF-41, which should remove any doubts about target coverage. The number of DF-31A missiles is small, too — not much more than 15
to a recent assessment. If we add up the DF-4s and DF-31s that could threaten Alaska and Hawaii, that’s 50-60 ICBMs, each with one warhead.
At least that was the case.
Each of these missiles had only one warhead because China’s nuclear warheads were really, really big. Beijing developed the DF-5’s original warhead in the 1970s and 1980s, when China was impoverished. The warhead for the DF-31 was developed during the early 1990s and is lighter — an
470 kilograms — but still big and heavy enough that the DF-31 and DF-31A could carry just one apiece.
The U.S. intelligence community has long asked what would happen if China put the smaller DF-31 warhead on the giant DF-5. Leaked U.S. estimates suggest that it could accommodate 3 or 4 such
. So why hasn’t China put multiple warheads on the DF-5?
China would surely prefer to retire the older DF-5 warhead design in favor of a more modern design. And using the newer, smaller warhead leaves tons of room. Literally tons. The DF-5 has between 3,000 and 3,200 kilograms of “throw weight” (that’s how much stuff it can heave across the globe). Even if about half the payload goes to the post-boost vehicle, there’s enough oomph left over for three or four 500 kg warheads. What else would one do with all that space? Add some penetration aids (decoys and so forth) to defeat missile defenses? Sure, but that’s a couple hundred kilograms max. Fill it with ballast for stability? Or maybe those little balls from
?
Here we come to an important observation about the risks of inferring intentions from capabilities. We act as if there is something morally compromised about placing multiple warheads on missiles. (Those sneaky Chinese!) Sorry, but there isn’t. The Russians do it. U.S. Strategic Command
to keep doing it as late as 2007. And the United States and Russia, along with France and Britain, all have multiple warheads on submarine-launched ballistic missiles. Yes, land-based MIRVs are an attractive target for a preemptive strike, which makes them destabilizing — but how destabilizing depends on the context. And at the moment, I have bigger worries about whether U.S. and Chinese nuclear forces will be stable in crisis.
Chinese officials don’t even use the phrase “minimum deterrence,” which American experts take to mean a small force that exists only to deter nuclear attacks. The Chinese
“lean and effective.” That is a lot like minimum deterrence (and hey, I liked the phrase “minimum means of reprisal” so much I
a book after it) but minimum deterrence is
ourterm, not theirs. And it doesn’t make any sense to try to infer Chinese intentions using U.S. strategic concepts.
The right way to think about China’s nuclear posture is to imagine a hypothetical policymaker who places far less emphasis on the details than a hypothetical American one would. Remember that 1958 article by the nuclear strategist Albert Wohlstetter, “The Delicate Balance of Terror”? As far as I can tell, Chinese weaponeers and political leaders by and large don’t think the balance is delicate at all. We can argue about whether that was Maoism or bureaucratic prerogative, but there is no arguing that China’s nuclear force is small. (Well,
no arguing.)
The Chinese nuclear posture, instead, has been driven by an enthusiasm for reaching technological milestones, not big deployments. American experts sometimes describe the missiles in China’s first series– the DF-2 through DF-5 — in terms of their range. China could first hit U.S. bases in the Philippines, then the Japanese island of Okinawa, then Guam, and so on. But that’s not how the Chinese describe these missiles. An official history of China’s missile program,
, describes its missiles in terms of its technological accomplishment on the path toward the ultimate accomplishment — an ICBM. The DF-2 was the first indigenously produced missile, the DF-3 the first cluster of engines, the DF-4 the first use of missile stages (one engine stacked atop another), culminating in the 1980s in the DF-5 — a large, powerful ICBM.
Of course, it is possible the Chinese don’t know what it means any more than we do. It wouldn’t be the first time a nuclear power undertook an open-ended nuclear modernization without any clear sense of the final destination. If Chinese policymakers are unthinkingly ticking off technological achievements — just as we Americans unthinkingly chase new missile defense and conventional strike capabilities — then the two parties could stumble into an arms race without really choosing to do so. That seems like what we should be discussing.
