Why is the US shifting its missile defense out of Europe?

Shooting down incoming missiles is notoriously difficult, despite rosy claims of success. But the potential for it both soothes populations and riles governments. Here's an update.  

Q: How effective are today's antimissile systems?

The famous "Scud busters" of the first 1991 Gulf War were American-made Patriot missiles deployed to Israel. While their success rate at the time was claimed to be 96 percent (later revised to 60 percent), Israeli Defense Minister Moshe Arens said later that their impact was "minuscule and, in fact, meaningless." Evidently, the inflated claims were propaganda. The aging Russian-made missiles launched by Iraq's Saddam Hussein had their own problems: They tended to disintegrate in flight.

An Israeli-developed antimissile system called Iron Dome reportedly had more success against short-range missiles fired into Israel by Gaza militants in November last year. Israeli government figures put its success rate at 84 percent, but independent video analysis said it was closer to 40 percent, and other estimates put it much lower.

Q: Why is the US canceling its European missile 'shield' and setting one up on its West Coast?

US Defense Secretary Chuck Hagel recently announced the cancellation of an antimissile deployment in Europe. Experts point to two reasons: money and North Korea. Mr. Hagel also said the United States would put 14 interceptors in Alaska by 2017, to counter a rising threat from North Korea's aggressive nuclear-weapons and missile program. North Korea has been testing longer-range missiles and recently completed a second successful test of an atomic bomb in February. (Scientists say Pyongyang's ability to miniaturize a nuclear weapon and put one in a missile is years away.)

Hagel's announcement about the missiles in Europe, while greeted with official nonchalance by Russia, could still warm up US-Russian ties. Russia has long objected to the prospect of missiles in Europe, saying they could target the intercontinental ballistic missiles (ICBMs) that are the bulk of Russia's strategic nuclear deterrent. Russia's concern had led it to repeatedly threaten to leave the START nuclear-arms reduction talks.

Q: How might the unilateral stand-down play in the US and Russia?

Conservative critics of the Obama administration may smell a rat. To them it may look like the fulfillment of President Obama's promise to then-Russian President Dmitry Medvedev, overheard by an open mike at a South Korean security conference a year ago. Mr. Obama told Mr. Medvedev that he would be able to show the Russians "more flexibility" on missile defense after he was reelected in November.

And Russian conservatives are suspicious, too. The shifting of a few missiles does not change what they perceive as a US plan for unchallenged military superiority. Missiles in Alaska, they say, could still hit Russian ICBMs.