President Obama began his trip to Israel by visiting an “Iron Dome” missile defense battery. Israel claims that Iron Dome intercepted nearly 90 percent of Hamas rockets launched during Operation Pillar of Cloud. However, experts are beginning to raise concerns about the effectiveness of the IDF’s rocket defense shield. Noted missile defense skeptic Theodore Postol has conducted a partial investigation into Israeli claims about the system’s effectiveness, and argues that the IDF is wildly overstating its intercept success rate, perhaps by a factor of ten or more.
A full evaluation of Dr. Postol’s claims requires a more complete technical study of Israeli intercept data. However, given Postol’s track record in debunking past claims of interceptor success (most notably the record of Patriot missile batteries in the first Gulf War), and the long history of exaggeration by missile defense advocates, skepticism is clearly warranted.
We should also note that the IDF has several good reasons to mislead the world about the effectiveness of Iron Dome. Part of the point of the system is to deter rocket launches, and if neither Hamas nor Hezbollah believe the system works, they will presumably not be deterred (although given the expense of a successful interception, they may not be deterred in any case). Similarly, some have argued that Iron Dome rendered a land invasion of Gaza unnecessary, under the logic that the IDF would have been under great public pressure to attack in the absence of an effective defense system. To call this claim “speculative” radically overstates its evidentiary foundation.
Perhaps more importantly, missile defense systems are expensive, and the Israeli public likes to know that its money is being well spent. Engineers and military officers may determine that keeping up appearances is likely to result in a public more ready to pour money into the system. Iron Dome is the first step in a much larger “system of systems” designed to defeat rockets and missiles. Admitting that Iron Dome doesn’t work would put the other elements of the system in jeopardy. Finally, several foreign countries have expressed an interest in Iron Dome technology; this interest would likely evaporate if questions developed about the effectiveness of the system.
Any reduction in Iron Dome’s effectiveness exacerbates cost-effectiveness problems. At best, Israel is spending $40,000 for a 90 percent chance of shooting down a rocket that may cost less than $1000. If the projected intercept rate goes down, attempts begin to look like increasingly terrible gambles.
Keeping all this in mind, we should take care in assessing claims about Iron Dome without having all of the evidence. Postol may be wrong, and the Israelis may have good data demonstrating the effectiveness of the system at the publicly stated intercept rates. Given the history of missile defense deception and the strong Israeli incentives to deceive, however, the people who pay for the system should be asking hard questions about how well it really works.