Some U.S. officials are pointing to Monday night’s success of Israel’s Iron Dome defenses—which shot down the vast majority of the hundreds of rockets fired from Gaza by Hamas, limiting Israel’s death toll to just seven—as bolstering the case for building more of our own missile defense weapons to ward off nuclear missile attacks by North Korea, China, Russia, or whatever other foe comes at us.
In fact, the comparison is completely invalid.
First, Hamas’ rockets fly slowly through the atmosphere. (A widely circulated video of the shoot-downs looks like it was shot in slow motion.) Ballistic missiles—which the U.S. systems are supposed to shoot down—arc into outer space and back down to Earth at 10 times the speed of sound. The former are fairly easy for radar to track and coordinate with a firing system; the latter are very difficult.
Second, over the years, Iron Dome has shot down about 80 percent of its targets. That’s an amazing success rate. But the U.S. system is designed to shoot down missiles tipped with nuclear warheads. If only 20 percent of those missiles got through, that would be a catastrophe.
Third, judging from tests over the past decade, the U.S. system would let in way, way more than 20 percent of enemy missiles. In fact, despite budgets of roughly $10 billion a year, every year, since President Ronald Reagan began the Strategic Defense Initiative (as it was originally called) back in 1983, the program—by all reasonable standards—has been a distinct failure. And it’s not getting any better.
According to a report issued last month by the U.S. Government Accountability Office, the Missile Defense Agency performed just two of its nine scheduled tests in 2020. One was a “no-test” (a software malfunction prevented the test from happening); the other was a failure. Both tests were meant to gauge the system’s ability to shoot down short-range ballistic missiles—the sorts of missiles that, for instance, North Korea has been frequently testing.
COVID was partly to blame for the delays, but, the report also noted, the Missile Defense Agency “has struggled over the past decade to execute its annual flight test plan.” In other words, even by federal standards, this is not a well-run program.
When tests are conducted, the results have been less than assuring. The interceptors have hit their targets just 50 to 60 percent of the time. According to a 2017 report by the Defense Department’s testing office, the systems demonstrated “a limited capability” to defend against “small numbers” of medium-range missiles and a “fair capability” against short-range missiles.
The system designed to shoot down long-range missiles—those with the range to hit targets in the U.S.—has performed successfully in just 10 out of 18 tests.
Part of the problem is that the mission is really hard. By comparison, the Iron Dome’s job is almost casually simple. A radar tracks the incoming rockets and sends the data to a battle management system, which fires and guides the interceptor. A proximity fuse onboard the interceptor is set to explode when it comes within 10 meters of the target. The shrapnel from the blast destroys the incoming target.
To shoot down a hypersonic ballistic missile as it plunges down to Earth is much harder. Decades ago, when the U.S. first tried to develop anti-ballistic-missile defenses, the idea was to arm an ABM rocket with a nuclear warhead—that is, to destroy an incoming nuclear missile with another nuclear missile. However, many objected on the grounds that many American people below would be killed by radioactive fallout.
In more recent schemes, the idea has been for the interceptor to ram into the incoming missile—a feat likened by some to hitting a bullet with a bullet. It is remarkable that the thing has worked at all. It is understandable, but unacceptable, that it doesn’t work very often.
As dismal as the official success rate seems, it is almost certainly exaggerated. First, in a test, the missile defense system’s operators know where the target—a mock warhead fired from a U.S. missile base—is coming from and when it was launched. They would not have such foreknowledge in a real war.
Second, no U.S. missile defense system has ever been tested against more than one target at a time. In other words, even if an enemy commander had an exaggerated belief in the technical prowess of the Missile Defense Agency’s wares, he could saturate the defenses by simply firing an additional weapon.
The irony of all this is that the Iron Dome is an American creation. The Israelis developed it, but, since 2010, the bills for producing the system—amounting to well over $1 billion—have been paid by the U.S government. This was done at the initiative of President Barack Obama (so much for the myth, spread by Benjamin Netanyahu and Donald Trump, that Obama was hostile to Israel) and approved, with near-unanimous votes, by Congress. Since its successes, the U.S. military has bought a small number of Iron Dome systems as well.
But Iron Dome isn’t so suitable to the threats faced by the United States. It can track and hit targets from a maximum range of 40 miles, whereas an interceptor designed to hit, say, North Korean missiles, even if fired from a U.S. military base in the Pacific, would need to detect a threat from hundreds of miles out.
All of this is well known to the officers running the Missile Defense Agency and to the officials who draw up the Pentagon’s annual budget. As John Pike, director of GlobalSecurity.org, puts it, “After four decades, almost no one believes in it, but we keep funding it nonetheless—the triumph of hope over experience.”