Back in April, the Obama administration announced a big shift in missile-defense priorities: It would move away from ambitious, technologically shaky "boost phase" defenses, and pour more money into fielding anti-missiles that might actually stop an attack from Iran or North Korea. This week, those retooled defenses get a big test – in Israel.

This week, the United States and Israel kicked off a major air-defense exercise that will test scenarios including coordinated missile barrages launched from Iran or from Syria, as well as shorter-range rocket attacks by Hezbollah or Hamas. The exercise, Juniper Cobra, is part of a series of biannual war games that dates back to 2001, but it's worth watching closely for several reasons.

First, there's politics. Brig. Gen. Doron Gavish, commander of the Israel Air Force’s Air Defense Division, said in a press conference that the exercise was not related to Iran's continued missile tests and enrichment of nuclear fuel. “It is a carefully designed exercise that has been taking place for years.” But Ha'aretz describes the drill as "preparation for a faceoff with Iran."

Case in point: Juniper Cobra includes a major civil-defense exercise that will test readiness against a catastrophic missile strike against an Israeli city. As part of the contingent of 1,000 U.S. troops taking part in the exercise, the Ohio Army National Guard's Chemical, Biological, Radiological, Nuclear and high-yield Explosive Enhanced Response Force will take part; the Guardsmen have been training with the Israeli Home Front Command as part of the exercise.

Some of the Obama administration's favored missile-stoppers will also be deployed for the exercise, including the Army’s Terminal High Altitude Area Defense (THAAD) and the Navy’s Standard Missile-3 (SM-3), part of the sea-based Aegis Ballistic Missile Defense.

The deployment of THAAD – pictured here in a 2006 test – is particularly important. “This unique system intercepts in an transitional area between earth’s atmosphere and space to include a range of 20 miles below and above the 62 mile or 100 kilometer line," said Riki Ellison, a prominent missile-defense advocate. "None of the current or future deployed missile defense systems intercept in this vertical space. Because of this vertical engagement area capability, the THAAD system can take multiple shots and use the atmosphere to strip off debris and countermeasures to better target the incoming warhead. The larger land-based missile defense system, the GBIs [Ground-Based Interceptors] as well as the sea-based missile defense system, the Aegis and SM-3, intercept above the 100k line at a higher altitudes in space, while the Patriot System ground-based system intercepts missiles in air below the atmosphere.”

The AN/TPY-2 radar – the powerful X-band radar that is part of the THAAD system – was deployed to Israel last year. Military officials have discussed tying this land-based radar to missile-defense ships offshore, creating a more mobile and flexible missile-defense system with wider coverage.

Finally, the exercise looks to be a pre-test of Iron Dome, a system being developed to provide defense against the short-range rockets like those fired by Hezbollah at northern Israel during the 2006 Israel-Lebanon war or the Qassams fired by Hamas from Gaza. While not fully operational, Iron Dome is also supposed to be integrated into the drill.

Writing at Esquire, Tom Barnett teases out the implications for Israel. "After almost a quarter-century of quiet cooperation with the Americans, Israel is now on the verge of perfecting a multi-layered missile-defense shield that protects against short-range rockets coming out of southern Lebanon and Gaza, plus anything Iran can toss its way," he writes. "Not only will Israel remain on the map following a potential first strike, it'll have second-strike capabilities secure enough to wipe off the map any fantasy-league roster of neighboring Islamic regimes you care to name."

[PHOTO: Wikimedia]