National Missile Defenses:

What’s new? What’s not? And, most important, does it make sense?

Lisbeth Gronlund

For the past several years, Congressional Republicans have sought to mandate deployment of a national missile defense (NMD) system, designed to defend the United States against a small number of long-range ballistic missiles. According to its advocates, the system could defend against a small accidental or unauthorized launch by Russia; a deliberate, accidental, or unauthorized launch by China; and a deliberate attack by a hostile state that acquired long-range missiles in the future.

Until recently, the Clinton administration maintained that there was no current or potential missile threat to the United States that would justify the deployment of such a defense. At the same time the administration has pursued its "3+3" plan to spend three years developing a national missile defense–by 2000–that could then be deployed in another three years–by 2003, if a decision was made to deploy. Thus, for the first time since it deployed the Safeguard missile defense system in 1975, the United States has moved beyond conducting R&D, and is developing a specific NMD system to be deployed.

What’s New?

The administration made several changes in its NMD policy early this year. On January 20, Secretary of Defense Cohen announced that the deployment date would likely be delayed from 2003 until 2005, but that the deployment decision was still slated for summer 2000. This change in deployment date reflects the widespread realization that the timetable for the 3+3 program was completely unrealistic. Last year, the program was criticized as a "rush to failure" by a independent panel of missile defense experts headed by General Larry Welch, former Air Force Chief of Staff.

Cohen also declared that the administration expected there would soon be a threat to warrant deployment, and that the primary remaining criterion for deployment of a national missile defense would be technological readiness. This change in policy can largely be attributed to two things. First, a commission chaired by former Secretary of Defense Donald Rumsfeld concluded in its July 1998 report that North Korea and Iran could acquire the capability to strike the United States with ballistic missiles within five years of making a decision to do so (Iraq is also included in this category now that UN inspections have stopped), and that the United States might have little or no warning before missiles were deployed. Second, on August 31 North Korea conducted a flight test of a three-stage missile. Although the third stage malfunctioned, the flight test suggested that North Korea could plausibly develop an intercontinental-range missile in the next several years.

To keep the deployment option open, the Pentagon added $6.6 billion for deployment to its total budget for FY 1999-2005. With the nearly $4 billion already budgeted for development, this brings the total FY 1999-2005 budget for NMD to $10.5 billion.

The administration also sent a stronger message to Russia that it will seek to renegotiate the Anti-Ballistic Missile (ABM) Treaty to permit deployment of a US NMD system.(See box on ABM Treaty Restrictions.) President Clinton apparently informed President Yeltsin of US intentions to modify the treaty in a letter sent in January. However, in his January 20 press briefing, Cohen strongly suggested that the United States would withdraw from the treaty if Russia did not agree to the modifications. The White House has since been trying to soften that position, and continues to maintain that the treaty is a "cornerstone of strategic stability." It remains unclear what exactly US policy towards renegotiating or withdrawing from the treaty is.

What’s the Same?

Despite the change of deployment date from 2003 to 2005, the nominal decision date of June 2000 remains unchanged. The Pentagon will conduct a "deployment readiness review" to assess the technological readiness of the NMD system. The President will then use this information to make a deployment decision. The Pentagon plans four flight tests prior to its readiness review; the first of which is now scheduled for August 1999. However, all four of these flight tests will be performed using surrogate boosters and kill vehicles and not prototypes of the components that would actually be deployed. Tests of the new booster and the kill vehicle–described as two of the "most critical tests" by Director of the Ballistic Missile Defense Organization Lt. General Lyles–are not scheduled to take place until FY2001 and FY2003, respectively.

If the administration decides not to begin deployment of a US NMD system next summer, then development will continue so that a decision to deploy could be made in the future. This issue will then be revisited periodically.

The administration made its January announcements to give credibility to its NMD program, in the hope that it could buy itself some political breathing space. However, Congressional pressure for deployment has continued unabated. Senator Cochran introduced legislation mandating deployment of a national missile defense as soon as is "technologically possible," which passed in March (by a vote of 97-3) once the White House withdrew its threat to veto the bill. The House then passed (by 317-105) legislation stating simply "It is the policy of the United States to deploy a national missile defense." These two bills now have to be reconciled in conference between the Senate and House.

Does It Make Sense to Deploy an NMD System?

As with all policy issues, making a decision about whether to deploy an NMD system requires weighing the likely costs and benefits. On the benefits side, one needs to assess the likely operational effectiveness of such a system. On the costs side, it is important to understand and take into account the likely reactions of other states to a US deployment. We consider these issues below.

Technical Feasibility vs. Operational Effectiveness

The Pentagon has identified technical feasibility as the key remaining criterion for deployment of a national missile defense. The US NMD will use high-altitude hit-to-kill interceptors (which are designed to destroy their targets by ramming into them above the atmosphere), whose test record so far has been dismal. Since 1982, the United States has conducted 16 intercept tests of exo-atmospheric hit-to-kill interceptors. Only 2 of these 16 intercept tests scored hits, for a 13 percent success rate. And the test record is not getting better with time: the most recent successful high-altitude test occurred in January 1991 and the last 10 such intercept tests have been failures.

However, even if this test record were stronger, it would not address the more important question: Can a national missile defense be expected to work in the real world? In other words, will it be operationally effective?

Even if all four of the NMD intercept tests planned between August 1999 and June 2000 take place and are successful, the United States will not have learned or demonstrated anything about whether the system would be operationally effective. A fundamental problem is that in the real world defenses will not face cooperative targets. Effective countermeasures can be cheap and use simple technology–much simpler than that required to build a long-range missile in the first place. Despite decades of research, dealing with countermeasures remains the key unsolved–and likely unsolvable–problem facing missile defenses. Indeed, this is precisely why the current program objectives call only for defending against "simple" warheads–those without effective countermeasures. However, if the United States deploys a national missile defense, it must expect that any developing country willing to expend the resources to build or buy intercontinental-range missiles to deliver an attack would also make sure it had countermeasures to penetrate the defense.

For biological or chemical weapons, the warhead can readily be divided into dozens of small bomblets, or submunitions, that would be released from the missile soon after boost phase. Not only would these numerous targets overwhelm a national missile defense, but this is a more effective way to disperse such weapons than using a single warhead.

For nuclear weapons, which cannot be subdivided, the attacker can employ other strategies to defeat the defense. In particular, any defense using high-altitude interceptors has an Achilles’ heel. Above the atmosphere, where the interceptors would attempt to hit their targets, there is no air resistance and objects of different weights and shapes travel at the same speed and follow the same path. This allows a missile to carry a large number of lightweight decoys to confuse and overwhelm the defense. For example, one relatively simple approach would be to hide the incoming warhead in a mylar balloon, and then release numerous identical balloons along with it. The defense would be unable to find the real warhead, and would run out of interceptors by trying to shoot at all the balloons.

Thus, in the real world, defending against a handful of warheads delivered by long-range ballistic missiles may be no more realistic than Reagan’s dream of building an impenetrable shield against the Soviet nuclear arsenal.

National Missile Defenses in Context: The Blackmail Scenario

Some argue that the United States needs a national missile defense to avoid being "blackmailed" by states that might try to deter US intervention in a military conflict by threatening to attack US cities with missiles carrying weapons of mass destruction. For example, the argument goes, if North Korea invaded the South it could deter the United States from aiding its ally by threatening Los Angeles with a nuclear-tipped missile but, the argument continues, the United States would not be deterred if it had a national missile defense to protect Los Angeles. This is a dangerous proposition. No missile defense system would be reliable enough that US leaders should be willing to risk Los Angeles based on its effectiveness. In practice, the United States would still need to rely on diplomacy or other means to counter such a threat.

The Emerging Missile Threat in Context

If the United States moves forward with deploying a national missile defense, how might other countries respond? First, consider the emerging missile states that the United States fears might threaten it with long-range missiles armed with nuclear or biological weapons (North Korea, Iraq, and Iran). If these countries do seek to threaten the United States with weapons of mass destruction, they have other delivery options.

As the Rumsfeld Commission pointed out, short-range missiles–which are much easier to build than long-range missiles–could be launched from off-shore boats and thus might present a nearer-term threat to the United States than long-range missiles. But a national missile defense would be useless against such short-range missiles, which would land before the interceptors could reach them.

And, according to Gen. Henry Shelton, Chairman of the Joint Chiefs of Staff, the United States will need to "assess where the ballistic missile threat is in the grand scheme of things." Even if North Korea does deploy long-range missiles that can reach the United States, this would not fundamentally change its ability to threaten the United States with weapons of mass destruction. North Korea already has at its disposal other ways to get such weapons to the United States, namely, by terrorist-type attacks such as truck-bombs, suitcase-bombs or weapons brought into a harbor by ship. As Shelton put it, ". . . there are adversaries with chemical and biological weapons that can attack the United States today. They could do it with a briefcase–by infiltrating our territory across our shores or through our airports."

Russia and China:

Perhaps most serious, the negative reaction from Russia and China to the US deployment of a NMD system could result in large security costs to the United States. Unfortunately, Russian and Chinese political leaders are unlikely to be confident that US missile defenses can easily be countered with penetration aids of the type discussed above, and thus will also react in other ways to preserve their deterrent capabilities.

Russia is deeply opposed to US national missile defenses and such a deployment will almost certainly scuttle the ongoing nuclear arms reduction process, which would otherwise cut Russia’s nuclear arsenal by many thousands of warheads. Russia’s collapsing economy will not force it to disarm unilaterally–as many in Washington seem to believe–but only to keep its multiple warhead missiles and operate its still substantial nuclear forces less safely. Perversely, moving forward with a US national missile defense would likely block those steps that would be most effective in reducing the missile threat to the United States–very deep reductions in Russia’s nuclear arsenal. Moreover, US deployment could actually increase the chance of accidental or unauthorized attacks by inducing Russia to rely more on launch-on-warning of its nuclear forces to preserve its deterrent.

China, too, is deeply opposed to a US national missile defense system. It has only some two dozen long-range missiles now, but has said it would seek to upgrade its nuclear arsenal in the face of US defenses. And if the United States and Russia remain stuck at relatively high levels of nuclear weapons, it will be impossible to get China and the other smaller nuclear weapon states involved in the nuclear arms control process.

Ultimately, US deployment of a national missile defense would likely put political and military barriers in the way of deep reductions in nuclear weapons. This would be a very high price to pay for a system that is unlikely to work in the real world.

Lisbeth Gronlund

Senio Staff Scientist, Union of Concerned Scientists

Research Fellow, Security Studies Program, MIT



ABM Treaty Restrictions

Article 1 of the Anti-Ballistic Missile (ABM) Treaty flatly prohibits deploying a defense that can cover the entire territory of the country. The treaty does permit each country to deploy a missile defense system with up to 100 interceptors at a single site, but only for a defense of an "individual region." Russia is permitted a defense around Moscow, whereas the United States chose as its site Grand Forks, North Dakota to allow protection of its ICBM fields.

Moreover, it is not enough that the interceptors be limited to one site; the ground-based battle-management radar (which tracks the incoming missiles and guides the interceptor to near its target) must be located at the same site. In fact, this restriction is consistent with the constraint that only an individual region may be defended. Because of the curvature of the earth and the large size of the United States and Russia, a radar at any one site in either country cannot see missiles landing on the entire country, and thus a single-site system cannot defend either country.

If a sensor system other than the ground-based radar is used to provide coverage beyond the field-of-view of the radar then such a system would be substituting for the radar, and thus falls under the provisions of Agreed Statement D, which states that such systems would be subject to negotiation. Unless such systems are specifically permitted, they remain illegal. Thus, deployment of the space-based sensor system (the low-earth orbit component of the Space-Based Infrared System or "SBIRS-low") that the United States is developing to track missiles and provide information to defense interceptors is illegal, as Russia has argued.


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