While there has been lots of discussion of the U.S.-Russia Strategic Arms Reduction Treaty (New START) over the past few months, one very important consideration continues to receive insufficient attention: China’s robust nuclear-force modernization program.

It is not clear the administration or lawmakers have thought through the implications of the fact that as we build down our strategic nuclear forces (by some 20–30 percent under New START) in the White House’s hope of playing Pied Piper to others on the road to “global zero,” the People’s Republic of China is building up its strategic nuclear forces.

As Congress could vote on whether to ratify the treaty in the coming days or weeks, now would be an excellent, indeed critical, time to consider this matter, especially since passing the arms-control pact will obligate us to its provisions for the next ten years.

While the exact shape of China’s ambitions may not be completely clear, there is little question that its aspirations are grand. In congressional testimony last year, then–director of national intelligence Dennis Blair said that Beijing’s international behavior is driven in part by a “longstanding ambition to see China play a role of a great power in East Asia and globally.”

To this end, China has been feverishly building all aspects of its national power: political, economic — and most worrisome, military. China’s military modernization has proceeded at a feverish pace; its defense budget has increased by roughly 10 percent per year over the last two decades.

On the nuclear front, China relies on the services of its strategic-rocket forces, known as the Second Artillery Corps. The Second Artillery has long been equipped with a small force of liquid-fueled, silo-based intercontinental ballistic missiles (ICBMs) armed with three- to five-megaton thermonuclear warheads such as the CSS-3s and -4s. But in recent years, it added a number of solid-fueled, road-mobile missiles such as the DF-31A, reducing the reaction time associated with the silo-based force while increasing survivability.

In addition, in its annual report to Congress on China’s military power, the Pentagon warns this year that China has “the most active land-based ballistic and cruise missile program in the world.” It may also “be developing a new road-mobile ICBM, possibly capable of carrying a multiple independently targeted re-entry vehicle (MIRV),” which can strike different targets, even though they are carried on a single ICBM. MIRVing of Chinese missiles will also mean that the number of warheads “could more than double in the next 15 years,” according to the Department of Defense (DOD). The Pentagon further notes that the People’s Liberation Army (PLA) is working on maneuvering re-entry vehicles (MARV), decoys, chaff, jamming, and thermal shielding for its strategic forces, increasing their ability to reach their intended targets.

And the problems do not end there. China’s Second Artillery has reportedly built 3,000-plus miles of tunnels in northern China, known as “The Underground Great Wall.” Some believe the tunnel system is intended to conceal China’s growing nuclear arsenal, while providing Beijing with a land-based nuclear capability that could survive an enemy’s first strike.

But it’s not just the Second Artillery that is getting a boost. Beijing is also diversifying its nuclear dossier from its longstanding “monad” of land-based nukes into the more traditional “triad” of land-, sea-, and air-based nuclear forces embraced by other major nuclear powers such as Russia and the United States.

Nowhere is this transition more dramatic than at sea. During the Cold War, Soviet and American submarine forces were considered the stealthiest and most survivable arm of the nuclear triad, especially in providing for a second-strike capability. Well aware of this, China is now sending its nuclear deterrent below the waves.

China’s new class of strategic submarine, the Type 094, has replaced its long-troubled first-generation fleet ballistic missile submarine (SSBN), the Type 092. The Type 094 may already carry twelve of China’s first intercontinental-range, sea-launched ballistic missiles, the JL-2, whose range exceeds 4,000 miles. Two or three of the boats may be in service already, with another two to three on the way. Beijing is building another SSBN, too, the Type 096, which is expected to be able to carry as many as 24 intercontinental-range missiles.

China is adding an air leg as well, most notably via the upgraded, nuclear-capable B-6 Badger bomber, originally of Cold War vintage. Analysts believe that China, which is already capable of dropping nuclear gravity bombs, is developing land-attack cruise missiles for these aircraft, which may have both conventional and nuclear warheads.

While these weapons are all of great interest, one must also look at the policy context in which these strategic systems reside. Not surprisingly, there is increasing debate in U.S. security circles about how China’s new strategic instruments fit into Beijing’s nuclear policy — a pressing issue, considering that PLA scholars often describe the American military as its most likely adversary.

China has long adhered to a no-first-use policy, meaning it promises not to use nuclear weapons against a non-nuclear state, in a nuclear-free zone, or to initiate a nuclear war. Beijing has also embraced a minimum-deterrence strategy, meaning that if deterrence fails, it plans to absorb a first strike and then retaliate, focusing on countervalue targets (i.e., population centers) rather than counterforce targets (i.e., the enemy’s nuclear forces).

China continues to espouse these policies publicly, but outside observers are starting to ask questions. According to some PLA watchers, there is an ongoing, behind-the-scenes debate in China about its nuclear policies, especially among the new generation of security strategists, who wonder if their seniors are failing to adapt to the country’s elevated position in the international pecking order. Some speculate that China may be considering shifting to a new nuclear strategy, which includes a preemptive, first-strike capability, which is aimed at destroying an opponent’s nuclear forces before they can launch.

Making matters more complex is China’s refusal to provide transparency or discuss its nuclear forces. The PLA has a general penchant for strategic denial and deception, which is perhaps nowhere better demonstrated than in its unwillingness to talk about nuclear issues with the Department of Defense. This lack of openness and dialogue presents a challenge to our intelligence and policy communities, since it perpetuates a litany of unanswered questions about China’s strategic doctrine, capabilities, and intent.

And while China’s strategic forces are increasing in number, diversity and capability, American nuclear forces are in desperate need of modernization. In the view of some experts, if any country can undertake a “rush to nuclear parity” with the United States, it is the world’s No. 3 nuclear power, China.

Indeed, according to some independent groups, Beijing could become a nuclear peer of Washington’s in the not-too-distant future if it so desired, in light of the expected arms cuts by the United States under New START.

The question remains: Have we really considered what China’s nuclear forces will look like over the life of New START? If not, we had better do so immediately.

Consequently, in considering New START, the Senate and the administration must factor in the trajectory of China’s nuclear forces and the direction of its strategic policy to ensure that an arms-control treaty with Russia does not undermine our security.

Peter Brookes is a Heritage Foundation senior fellow and a former deputy assistant secretary of defense.