A senior Israeli official says the new David's Sling anti-missile system should be operational within three years but this month's battle against Palestinian rockets underlined how time is the enemy for the Jewish state.

The Israelis' race to set up a credible air defense shield against missiles and rockets -- the weapons of choice for most of the country's adversaries -- is linked to Israeli Prime Minister Binyamin Netanyahu's threat to launch pre-emptive strikes against Iran's nuclear infrastructure.

If such attacks are unleashed, Israel could expect Iranian retaliation that would inevitably include a massive ballistic missile assault, along with missile and rocket attacks by Hezbollah in Lebanon, on Israel's northern border, and the Palestinian militants in Gaza on the country's southern flank, on an unprecedented scale.

It can be argued that Netanyahu and his fellow hawks, who are likely to strengthen their hold over Israel's Parliament in January elections, are reluctant to launch strikes against Iran until they have effective defense systems in place.

But that depends on how Iran's alleged nuclear weapons drive progresses. Any Israeli strike would have to be before Tehran actually is able to produce nuclear arms.

In the meantime, Iran's producing more Shehab-3 ballistic missiles and working on a more advanced model, the Sejjil-2.

The undoubted success of the Iron Dome system -- the first of its kind -- during clashes with the Palestinians, in engaging Grad-type rockets and longer-range Iranian-built Fajr-5s, has resonated deeply with Israelis.

This belief that they're now pretty much protected against missiles and rockets has been encouraged by military and government officials, who sing the praises of Iron Dome, developed by state-owned Rafael Advanced Defense Systems of Haifa.

Some 1,500 Palestinians rockets killed only three Israelis. Iron Dome shot down 421 of those it engaged -- and it only intercepts missiles its computerized system calculates are going to hit populated areas or infrastructure.

The rest of the rockets exploded harmlessly in open ground. Only a handful got past Iron Dome.

The Jerusalem Post observed in an analysis of "the true strategic significance of Iron Dome" that it's "a game-changer that not only consigns Hamas' and Hezbollah's current terror model to the trash can, it completely undermines the military doctrines of all Israel's enemies."

That's undoubtedly true, for now anyway.

Iron Dome, originally designed to intercept rockets with a maximum range of 40 miles, has been upgraded. One of the five batteries in action was an upgraded version with an extended range of up to 180 miles and improved radar.

That means it's already filling a gap in Israel's planned four-layer missile defense system by tackling mid-range weapons like Fajr-5.

Commentator Akiva Hamilton argued in the Post under the headline "Bankrupting Terrorism," that in financial terms its costs Israel's enemies more to build, transport and deploy their missiles than its costs Israel to manufacture and deploy Iron Dome with its kill rate of 90 percent.

Hamilton predicted that will increase to 97.5 percent eventually.

This, the argument goes, will be duplicated by David's Sling, the mid-range system also being developed by Rafael with Raytheon of the United States.

But David's Sling isn't expected to become operational until 2015, said Isaac Ben-Israel, a former general who heads Israel's Space Agency.

Only two batteries will be required to cover the country, he said. Military planners say at least 13 Iron Dome units, maybe more, will be needed.

David's Sling passed its first test-firing against a missile in southern Israel Sunday.

Equipped with radars built by state-owned Israel Aerospace Industries, it's intended to counter Syria's M600 missile plus Iran's Fajr-5, Fateh 110 and Zelzal weapons, all of which Hezbollah possesses in large numbers.

It has many more missiles than Hamas and its allies -- in excess of 43,000, Israel says.

Hezbollah can fire hundreds of missiles within minutes, which skeptics believe could overwhelm Israel's air defenses.

Israeli hard-liners describe the battering of Gaza every three or four years by Israel's powerful military as "mowing the grass," wearing down Hamas' military capabilities without the need to negotiate compromises.

"The military weakness of Palestinian factions in Gaza allows Israel to carry out such offensives at relatively low risk," observed Beirut security analyst Nicholas Blanford, "something that cannot be said about a strike against Hezbollah -- or against Iran."