Debating Missile Defense: Tracking the Congressional Record

March 2021
By Leah Matchett

“When you vote [against missile defense] as a member of Congress, you are telling your own 575,000 constituents in your district that you are going along with an agreement that leaves them exposed deliberately to missile attack," according to U.S. Representative Duncan L. Hunter (R-Calif.).1 Hunter, a strong proponent of missile defense, put his finger on a challenge that missile defense skeptics in Congress have faced for years: it is difficult to vote against “defense.”

A Missile Site Radar stands long-abandoned in Nekoma, N.D., where the United States briefly operated the Safeguard anti-ballistic missile system in the 1970s. The radar guided two types of nuclear-armed interceptors to protect U.S. ICBM silos.  (Photo: Terry Robinson/Flickr)The arguments from the expert academic and strategic nuclear policy community against homeland missile defense, which largely focus on the strategic impact of missile interceptors in stimulating countermoves, technical challenges, and high costs, have mostly ignored this feature of the politics surrounding the issue. Particularly in recent years, opponents of missile defense in Congress generally have failed to make key strategic arguments. This article outlines key gaps in congressional arguments against national missile defense aimed at defending the American public from a nuclear attack.

Close examination of the congressional debate on national missile defense shows a significant distinction between how members of Congress talk about these systems and how the expert academic and nuclear policy community does. The following analysis is based on a computerized model of congressional debates on missile defense to explore these dynamics. The data suggest that when considering the technical feasibility of missile defense, members of Congress express views that track closely with the debate in the academic nuclear policy circles. Yet, members of Congress who are critical of missile defense have largely ignored the debate over its strategic shortcomings, instead focusing on cost and trade-offs. This leaves the “defending the country” argument unanswered and misses a real opportunity to leverage the arguments of experts on the strategic risks of missile defense. It also reflects the broader worry Democratic members of Congress have about being seen as soft on defense, which is an outcome that need not be inevitable.

Congress Listening to the Experts on the Technical Challenges

Since the earliest days of congressional debate about missile defenses, arguments about its desirability have been inextricably intertwined with questions about its technical feasibility. There was so much skepticism about the prospects for President Ronald Reagan’s Strategic Defense Initiative (SDI) program, for instance, that opponents dubbed it “Star Wars” after a literal fiction.

Part of the reason for the slew of fanciful technology that has been proposed for missile defense over the years—everything from “rods from god” to X-ray lasers—is that missile defense is a difficult problem. Immediately following an offensive ballistic missile launch is its boost phase. Targeting it during this phase with a missile defense interceptor is fairly straightforward, due to the high heat signature of a booster rocket. Missiles remain in this stage, however, for a very brief period. In order to successfully intercept a rocket fired from China or Iran during the boost phase, the intercept would likely have to be initiated within seconds of launch and the interceptor stationed inside or directly adjacent to the country in question—an unlikely prospect.

After the missile finishes the boost phase, it enters a midcourse stage, where it travels through space and the outer atmosphere along a ballistic trajectory. A significant number of U.S. missile defense programs have been designed to target enemy missiles at this stage, but the incoming rocket can easily deploy decoys, some as simple as mylar balloons. In space, these travel at the same velocity as the missile itself and are difficult to distinguish from an incoming nuclear-armed warhead, making interception challenging.

Once the missile and the decoys reenter the atmosphere, they quickly become distinguishable, marking the terminal phase of missile flight. During this phase, missile defense systems have a very limited time to target an incoming missile, usually less than a minute. Because of this, terminal-phase interceptors are most effective in a small area surrounding the interceptor’s launch site. In the words of the Missile Defense Agency (MDA), “[I]is like a catcher behind the plate in a baseball game. As long as the pitch is near the plate, the catcher can catch the throw.”2

Kinetic missile interceptor technology has improved over the decades, a point often highlighted by proponents of missile defense in Congress.3 Representative Trent Franks (R-Ariz.) in 2009 described in detail a successful test of the Terminal High Altitude Area Defense system, providing information about how the “interceptor hit the target dead center and blew it to smithereens.”4 On another occasion, in 2001, Representative Scott McInnis (R-Colo.) noted, “We had a test…. It was a remarkable test. It shows that we are well on our way towards coming up with the technology that is necessary to deploy a missile defensive system for our country.”5

A SM-3 Block IIA is launched from the USS John Finn, an Aegis Ballistic Missile Defense System-equipped destroyer, November 16, 2020, as part of Flight Test Aegis Weapons System-44 (FTM-44). (Photo: U.S. Missile Defense Agency)This testing has drawn its own critiques from the expert academic and nuclear policy community. For years, the testing of missile defense systems did not involve realistic scenarios such as countermeasures against intercept. Although the realism of testing has improved, critics note that the United States has never carried out a strategic missile defense test against multiple simulated targets, at night, or when the sun is in the interceptor’s field of view, which could make for a more challenging sensing environment.

Just as proponents of missile defense rely on evidence from successful tests, opponents in Congress are quick to note when a test has failed. In 2003, Representative Dennis Kucinich (D-Ohio) declared that “[n]ational missile defense does not work. It has failed three tests that were much simpler than real-life scenarios.”6

Lieutenant General Sam Greaves, head of the MDA, has dismissed the problem by simply saying that the MDA “tests against the types of threats we expect our adversaries could employ.”7

Proponents of strategic missile defense systems also note that the testing record has improved dramatically in recent years, and more complex tests are being carried out as the system develops and the program sees continued financial investment.

These technical challenges and the efforts to overcome them have become a key part of the expert debate on missile defense and one largely mirrored by the congressional debate.

Using computerized text analysis methods, this history of congressional committee debates on missile defense programs from 1995 to the present, which total almost a half-million statements, produces a vectorized model of text, a computer model that preserves the context of words and allows the researcher to ask questions about the context in which a particular discussion occurs. This model was used to determine the most important partisan differences in congressional discussion of missile defense.

The data shows that both parties spend significant time debating the technical feasibility of missile defense. Republican statements tend to focus on “atmospheric intercepts,” “demonstrations,” and “programmatic feasibility,” while Democratic members of Congress tend to echo outside experts’ concerns over testing validity, stressing the need for “independent validation,“ more “extensive oversight,” and “proven scalable technologies.”

In general, Democratic members are more critical of the technical prospects for missile defense, including an emphasis on the need for a “fundamental rethink” and a look at “assumptions underpinning” the system, while the Republicans are more bullish, often emphasizing “revolutionary concepts” and “American exceptionalism” in the context of missile defense.

These debates are largely similar to the expert debate, with one side expressing skepticism of technical feasibility and the other noting progress through time and expressing confidence in the future. Where members of Congress diverge from the academic and nuclear policy community on missile defense is mainly with respect to the discussion of its strategic consequences.

Failing to Make the Strategic Case Against Missile Defense

Most proponents of homeland missile defense are aware that it is unlikely to constitute perfect protection from missile threats, particularly against adversaries with larger arsenals and more advanced missile systems. They suggest, however, that even limited protection would reduce the costs the United States would incur if struck by an adversary’s missiles, and this could be beneficial strategically in a number of ways.

One argument made in favor of missile defense is that it strengthens the extended deterrence commitments of the United States. Proponents argue that key allies rely on the U.S. commitment to employ nuclear weapons in defense of an ally—the so-called nuclear umbrella. A robust U.S. homeland missile defense, even with limited capability, could reduce the damage the United States is likely to incur in a limited nuclear exchange, thereby increasing the credibility of the U.S. commitment to defend allies against other nuclear-armed states. In the Congressional Record, discussion of missile defense is more likely to be associated with allies such as Israel, Poland, and South Korea than it is with adversaries such as Iran and North Korea. This suggests that a good portion of congressional debates also focuses on extended deterrence and the role of missile defense in alliances.

A separate argument made by advocates of missile defense is that any reduction in nuclear costs that the United States would pay increases its potential bargaining power in a crisis with a nuclear power. U.S. missile defense “could steel the country’s resolve in a war in which the enemy might well have long-range ballistic missiles,” thus leading to better outcomes crisis bargaining.8

Many expert critics of missile defense dispute this point, arguing that this reduction in costs is only meaningful if it changes the balance of U.S. costs and interests. If the damage the United States might suffer remains high enough, then missile defense does little to enhance the credibility of threats to escalate.9 If 100 million Americans are under threat, reducing that number to 50 or even 30 million would be admirable, but does not affect the willingness of the United States to incur those costs, because 30 million is still an unthinkably high price to pay for any foreseeable interest.10

Even so, proponents note it might be possible to avoid these costs altogether. As part of a crisis, some expert proponents of missile defense have argued that missile defense increases the viability of a preemption strategy against a state with a relatively small ballistic missile force.11 Preemption, in a nuclear context, involves wiping out the nuclear forces of an adversary before they fire. Usually, preemption is considered risky to the point of being infeasible. If the United States were to miss even one of an opponent’s missiles, it would be almost ensured a nuclear retaliation. Missile defense proponents argue that a robust missile defense system could deal with as many as 10 missiles that were not taken out by the preemptive strike, lowering the barrier to preemption.12 Critics of missile defense use this same argument to suggest that other states, aware of the increased feasibility of U.S. preemption, would face a “use it or lose it” dilemma. This could actually make them more likely to launch their nuclear weapons in a crisis.13

These nuanced debates are part of a long line of argument carried forward by scholars since the 1950s. During the Cold War, it was also a feature of the way Congress talked about these systems. It is only more recently that these arguments are largely missing from the Congressional Record.

After all, the rationale for the 1972 Anti-Ballistic Missile (ABM) Treaty between the United States and the Soviet Union was grounded in the strategic logic that the unconstrained deployment of large-scale strategic ballistic interceptor systems would only stimulate an even more massive build-up of the offensive strategic ballistic missile forces of each side, thus making the defenses irrelevant in an all-out conflict and making the Cold War nuclear arms race even more expensive for both sides.

This view was reflected in the critique offered on September 10, 2001, by then- Senator Joe Biden (D-Del.) at the National Press Club regarding the George W. Bush administration’s plan to withdraw from the ABM Treaty in order to deploy a more robust midcourse strategic missile interceptor system in Alaska.

Biden, who chaired the Foreign Relations Committee at the time, said implementation of the president's missile defense plan could trigger a new nuclear arms race involving Russia and China.

“Are we really prepared to raise the starting gun in a new arms race in a potentially dangerous world?” Biden asked. “Because make no mistake about it, folks, if we deploy a missile defense system that is being contemplated, we could do just that. Step back from the ABM Treaty. Go full steam ahead and deploy a missile defense system, and we will be raising the starting gun. Let's stop this nonsense before we end up pulling the trigger.”

Compared to the early focus by congressional critics on missile defense as a possible strategic loss, the data on more recent congressional discussions show a largely one-sided assertion that missile defense is good for nuclear deterrence that has gone largely unanswered.

In the text model, discussion of deterrence is one of the best ways to tell whether a statement was made by a Republican. Phrases such as “deterrence equation,” “deter enemies,” “deter coercion,” and “crisis deterrence” are an important part of the Republican justification for missile defense. In contrast, the Democratic Party overall has had relatively little to say about the strategic arguments against missile defense.

Instead, most Democratic members try to focus the discussion of missile defense on its very high costs. The words most likely to indicate that a statement on missile defense was made by a Democrat include those such as “exceedingly expensive” and “hidden cost,” or those that compare missile defense to trade-offs in other expenditures, such as infrastructure and health care.

It is these strategic arguments where the congressional debate on missile defense diverges most strikingly from the academic one. Although many Republican members of Congress talk about missile defense as an aid to deterrence, Democrats often do not directly rebut this argument and discuss strategic issues measurably less than their Republican colleagues. At the same time, missile defense as a whole has become less controversial. Throughout the Cold War, Congress routinely made significant revisions to the president’s proposed budget for missile defense, sometimes increasing or decreasing requests by as much as 30 percent. Now, these requests are often passed without significant changes.

The expert academic and nuclear policy community debate suggests that missile defense might be strategically undesirable, even if feasible, and might do little to affect deterrence calculation when such high stakes are involved. Democratic members of Congress, however, generally avoid the topic of deterrence. This is not to suggest that no critic of missile defense in Congress is making the strategic arguments against the system. These arguments can still be found.14 Yet, the data suggest that they are the exception and that most Democratic criticism of missile defense systems focuses on cost and feasibility.

The problem with the Democratic focus on cost is that there is no clear standard for how many tax dollars the government should spend to protect human life. It is unconvincing to answer a strategic argument (missile defense is important for the defense of the nation) with the suggestion that defending the nation is too difficult (feasibility) or too expensive (cost). This helps to explain why Democratic members of Congress debating missile defense often focus on trade-offs with other national security priorities.

The result of this gap is that a powerful academic argument, that missile defense is undesirable, even if economically and technologically feasible, because it makes the country less safe, is largely underutilized by congressional opponents of strategic missile defense. Many members of Congress could be unaware of this argument, although this seems unlikely. Given the high volume of debate on the issue over the years on this issue, there may be other reasons why these strategic arguments are not made more often.

Making the Argument: Moving Beyond ‘Soft on Defense’ Fears

One explanation for this gap is that the strategic argument against missile defense, although sound, is deemed a political loser by a Democratic Party that is constantly concerned about being branded soft on defense. Democrats from President Lyndon Johnson to President Bill Clinton have struggled with this aspect of missile defense. How do you tell the American public it is a bad idea to try to defend them?

The inability to answer this question, which left Democrats “groping for a way to respond” to the SDI program,15 stems fundamentally from a failure to effectively engage on the strategic arguments against missile defense. The way to respond to the argument made by Hunter that opposing missile defense means leaving constituents “exposed deliberately to missile attack” might be to make the counterargument: that homeland missile defense could lead a determined enemy to actually increase its offensive missile capabilities to evade or overwhelm any defense and that the best protection against missile attack is to reduce the possibility that there will be an attack in the first place.

The American public can and has responded to strategic arguments when presented with them. There is no reason to think that they would not do so in this case. As the Democratic Congress is grappling with the next steps for this system, it is essential they consider the strategic arguments. The first step to this is holding a hearing on the strategic arguments for and against homeland missile defense, including the consequences that continued expansion of this program is likely to have on arms control efforts.16

Public opinion is deeply shaped by elite cues. Work on public opinion and the use of military force suggests that same-party elites have a significant amount of influence on public opinion.17 Without leadership from opponents of missile defense within Congress pointing out the strategic problems with this technology, the public is unlikely to make the connection on their own.

The Biden administration and congressional Democrats should worry less about being considered soft on defense and more about how they can make good defense policy and explain their choices to the American public. Whether on missile defense or anything else, it is important to make the argument.


1. 141 Cong. Rec. H5,937-H5,977 (daily ed. June 14, 1995).

2. U.S. Missile Defense Agency, “Ballistic Missile Defense Challenge,” MDAfacts, January 30, 2004,

3. In the 1960s, the United States pursued the development of strategic missile defense systems that utilized interceptors armed with nuclear warheads. The Johnson/Nixon-era Safeguard program involved two types of interceptors: one armed with a five-megaton-yield warhead, another with a one-kiloton warhead. Following, the conclusion of the Anti-Ballistic Missile Treaty in 1972, the scope of the program was scaled back and focused on the defense of U.S. intercontinental ballistic missile launch sites. It was cancelled by Congress in 1975, the same year it officially became operational. Since then, U.S. missile defense research and development has focused on non-nuclear kinetic destruction technologies.

4. 155 Cong. Rec. H13,131-H13,139 (daily ed. May 20, 2009).

5. 147 Cong. Rec. H15,259-H15,265 (daily ed. July 31, 2001).

6. 149 Cong. Rec. H17,130-H17,158 (daily ed. July 8, 2003).

7. Mike Stone, “Lack of Real-World Testing Raises Doubts on U.S. Missile Defenses,” Reuters, August 9, 2017.

8. James M. Lindsay et al., “Correspondence-Limited National and Allied Missile Defense,” International Security, Vol. 26, No. 4 (2002): 190-196.

9. Charles L. Glaser and Steve Fetter, "Should the United States Reject MAD? Damage Limitation and U.S. Nuclear Strategy Toward China," International Security, Vol. 41, No. 1 (2016): 51.

10. Charles L. Glaser and Steve Fetter, "National Missile Defense and the Future of U.S. Nuclear Weapons Policy," International Security, Vol. 26, No. 1 (2001): 40–92.

11. Lindsay et al., "Correspondence-Limited National and Allied Missile Defense."

12. Ibid.

13. Glaser and Fetter, "Should the United States Reject MAD?”

14. See Kingston Reif, Twitter post, December 4, 2020,

15. Steven V. Roberts, “The Political Campaign; Reagan Emphasizes ‘Star Wars’ Plan on Stump,” The New York Times, October 27, 1986, p. A19.

16. Jeffrey Lewis, “The Nuclear Option: Slowing a New Arms Race Means Compromising on Missile Defenses,” Foreign Affairs, February 22, 2021,

17. Alexandra Guisinger and Elizabeth N. Saunders, "Mapping the Boundaries of Elite Cues: How Elites Shape Mass Opinion Across International Issues," International Studies Quarterly, Vol. 61, No. 2 (2017): 425–441.

Leah Matchett is a Knight-Hennessy Scholar pursuing a doctorate in political science at the Stanford University School of Humanities and Sciences.