Israel may have attacked targets in Syria – and risked a wider war – to stop ballistic missiles from falling into the hands of Islamic extremists. But current and former Israeli missile defense officials insist that if Hezbollah militants ever got the Fateh-110 weapons, Israel could shoot the missiles out of the sky.

"We are now able to cope with all the missiles that are threatening Israel right now, including the longer-range missiles in Iran and in Syria," Arieh Herzog, the former director of the Israel Missile Defense Organization, tells Danger Room.

Unless, of course, the extremists fired off a whole lot of the weapons at once.Israel's missile defense calculus and the decisions it makes based on that calculus have repercussions far beyond its own borders. The more vulnerable Jerusalem feels to indirect fire, the more likely the Israeli military is to hit missile stockpiles in places like Syria, as they reportedly did over the weekend. And the more that happens, the higher the chances that the already gruesome Syrian civil war escalates into a region-wide – or even global – conflict. (Already, President Obama under intense pressure to intervene more directly in the conflict.)

Israel's Iron Dome interceptor system kept hundreds of crude, unguided rockets from hitting Israeli towns during 2012's mini-war with Hamas. After the weekend's airstrikes on Syria – attacks that the Syrian regime vowed to avenge – the Israel moved a pair of Iron Dome batteries to its north, in order to counter the low-tech threat. But Iron Dome would be useless against the 27 foot-long, Iranian-made Fateh-110s, which can come crashing down on a targets hundreds of miles away at three and a half times the speed of sound. The missiles give Hezbollah the ability to blast Tel Aviv and nearly every other major Israeli city. Oh, and they might be capable of carrying chemical warheads, too.

Right now, Israel's missile defenders say they can counter the Fateh-110s, thanks to a different interceptor system called the Arrow-2. But that defense, like any defense, is imperfect. ("Rockets and missiles will hit us," says Col. Tzvika Haimovitz, who commands the Israeli Air Force's active missile defense wing. "My job is to minimize this number, to minimize the damage.") And unlike the Iron Dome, the Arrow-2 has never been tested in combat.

The Arrow has been in the works since the Missile Command era, when Washington and Jerusalem agreed to co-develop the interceptors as part of the Reagan administration's "Star Wars" push. Saddam Hussein's Scud missile attacks during the first Gulf War only heightened the need for some sort of protection. The first Arrow battery went operational at the turn of the millennium, and was designed to stop Scuds in the final few seconds before they strike. But it wasn't until a series of tests in the mid-2000s in California that upgraded Arrow-2s began to show that they might be able to handle the job, working with Green Pine phased array radars to find and detonate against a real Scud-B missile flying in from nearly 190 miles away.

Further improvements followed: a better ability to discriminate real weapons from fakes; an upgraded "Super Green Pine" radar; a single, nationwide system for controlling all of the country's Arrows; integration with Iron Dome and with the country's batteries of Patriot-3 anti-missiles. Today, the system can handle a weapon like the Fateh-110, Herzog says: "Basically, its range and typical trajectory is quite similar to the Scud B. The trajectory is similar, the size is similar, the warhead size is similar. Therefore you can imagine that the system designed to stop the Scud-B could be able to intercept it."

Which begs the question: Why chance a broader war in order to stop the weapons? After the airstrikes, Syria's cabinet declared that it had a duty "to defend its people by all available means," and UN Secretary General Ban Ki-Moon expressed his "grave concern" over the attacks.

"Israel's alleged airstrikes in the Damascus region play nicely into the hands of Assad and the Syrian regime," Haifa University professor Kais Firro tells Al Monitor, because the Assad regime can now label the rebels as tools of the Jewish State. "In fact, they’re celebrating. It’s exactly what they needed."

But the worry in Israel is that too many simultaneous attacks – especially simultaneous attacks from different directions – will overwhelm the Arrow-2. "It's quite easy to stop a single point of threat. Unfortunately, the battlefield situation is more complicated," Haimovitz tells Danger Room.

And a single Fateh-110 getting through could have devastating consequences if it hits a major city. It's one of the reasons why in its 2006 invasion of Lebanon, the Israeli military immediately targeted Hezbollah's missile and rocket launchers, destroying 59 in the first 34 minutes of the war.

"Basically the Fateh 110 is a long-range, guided, accurate rocket with a big warhead. Therefore it's a much more important rocket than the others Hezbollah has. Being accurate, they need to have a much smaller amount of rockets fired against a single target," Herzog says.

"Of course, there is a defense and we can intercept them," he adds. "But always interception is limited and there are always chances that the other side will be successful and penetrate the defenses. If they're accurate, it's much more problematic than an [unguided] type of rocket."

And while Arrow-2's test record is broadly successful, there have been glitches along the way, like the 2009 drill that was aborted when a Super Green Pine radar couldn't transfer targeting information to an older model.

A separate system, dubbed Arrow 3, is designed to serve as a kind of a back-up to – and improvement on – the current interceptors. It aims to hit a ballistic missile far earlier in its flight, while it's still flying through space. An initial stage is designed to to take the anti-missile past the atmosphere, and then a second stage interceptor maneuvers to crash into the target.The first "exo-atmospheric" test of the Arrow 3 was held in February, and was promptly proclaimed a success. The U.S. has already invested nearly $250 million in the new system – part of an estimated $1 billion sunk by Washington into the overall Arrow project. Israel is expected to ask for another $680 million for additional Arrow-3 batteries in advance of an initial deployment that's set for 2016. And even then, Israel is unlikely to stop the airstrikes if it sees another missile shipment it can hit.