The success of Israel’s Iron Dome defense system, which has intercepted 80 to 90 percent of the rockets launched from Gaza, is viewed by many as a cause for celebration. Worse, it’s being used as evidence that missile defense works.

In fact, the odds that missile defense can protect a state from inter-continental ballistic missiles armed with nuclear weapons are slim to nonexistent.

Equally troublesome, it’s an ongoing bone of contention between the United States and Russia. The United States seeks to implement defense systems in Europe ostensibly to protect the NATO countries from — however hypothetical — a nuclear attack by Iran.

Perhaps partly because of how preposterous the Iran pretext sounds and because it serves the purposes of the Russian defense establishment, Moscow views missile defense in Europe as an even larger affront to the stability of nuclear deterrence than missile defense on American soil. Currently, aside from a radar installation in Turkey, U.S. missile defense in Europe is deployed only on ships in the Mediterranean.

Meanwhile, drawing conclusions about missile defense from Iron Dome is like comparing apples and oranges. At Foreign Policy, Yousaf Butt explains.

That this small battlefield system has been so successful against the relatively slow-moving short-range rockets doesn’t mean that larger and much more expensive missile defense systems, such as the planned NATO system, will work against longer-range strategic missiles that move ten times as fast.

In other words, Iron Dome is not missile defense, it’s rocket defense (which, in fact, is also a subsection of U.S. missile defense).

In contrast to the short-range Hamas rockets, which fly through the atmosphere during their whole trajectory, the longer-range ballistic missiles … spend most of their flight in space. For decades it has been known that trying to intercept a warhead in space is exceedingly difficult because the adversary can use simple, lightweight countermeasures to fool the defensive system [such as] cheap inflatable balloon decoys.

Furthermore

… an 80 percent-effective tactical missile defense system against conventional battlefield rockets — such as Iron Dome — makes a lot of sense. If 10 conventional rockets are headed your way, stopping eight is undeniably a good thing. The possibility of stopping eight of 10 nuclear warheads, however, is less [impressive] since even one nuclear explosion will inflict unacceptable devastation. Just one nuclear-tipped missile penetrating your missile shield is about the equivalent of a million conventional missiles making it through.

Nor should we forget that

Even the largely successful Iron Dome system, while providing a worthy cover has not provided normalcy for Israeli citizens: the terror is still there.