Amy Butler Washington

Israel's new “Iron Dome” counter-rocket, artillery and mortar system has racked up a success rate above 80% since being fielded last year, but its weak link—as with most missile defense systems—is too few interceptors.

Israel plans to solve this problem in the short term by doubling the Rafael's Tamir interceptor manufacturing capacity. But some U.S. lawmakers are pushing the Pentagon to step in and coproduce the missile on U.S. soil, not only as a backstop for the Israel Defense Forces' supply but as a domestic capability that could protect deployed soldiers.

Iron Dome is the newest layer of Israel's budding air and missile defense capability. The Arrow-2 covers intermediate-range missiles. The PAC-3 and “David's Sling” systems handle the range between Arrow-2 and Iron Dome, which is designed to counter threats launched from 4-70 km (2.5-45 mi.).

These weapons are largely launched by Hamas and Hezbollah. Though many lack guidance—and some land harmlessly in unpopulated zones or the sea—Israel had to devise a way to counter them in order to maintain normal daily activities inside its borders, despite the threat, says Ilan Berman, vice president of the American Foreign Policy Council.

Four Iron Dome batteries, each capable of defending a medium-sized city, are deployed in southern Israel, and two more will follow next year, says Lt. Col. Merav Davidovits, missile defense liaison for the Israel Defense Forces in Washington. During a briefing Oct. 2 hosted by The Heritage Foundation conservative think tank, she declined to identify the current or planned capacity of the Tamir interceptor production line.

However, since the system was fielded in 2011, Iron Dome has intercepted roughly 100 rockets, a success rate of 80-90%. To avoid wasting interceptors, developers designed the system to discriminate among targets. The feature, called “selective engagement,” allows for the command-and-control element to assess the anticipated impact point of a rocket or mortar during its flight; it automatically disregards those headed for unpopulated areas or the sea.

“The system was successful not only with a single interception but also in a salvo situation,” Davidovits says, noting that often the Israel Defense Forces felt Hamas and Hezbollah were testing its limits by changing tactics, including launching rockets at night or during bad weather, or by trying to overwhelm defenses with salvos of threats. “We thank them for all the lessons learned that we gained,” she said. Israel has added undisclosed improvements based on operational experience.