Israel's airstrike against Syria Wednesday underlines just how jumpy the Israelis are as they grapple with a range of emerging threats on all their increasingly unstable borders.

"Instability on every border has created a new strategic environment in Israel," the U.S. global security consultancy Stratfor observed.

Syria's civil war, which will enter its third year March 15, is in a dangerous phase as the Damascus regime of President Bashar Assad battles for survival. It threatens to spill over into ever-volatile Lebanon, stronghold of the Iranian-backed Hezbollah, an implacable foe of the Jewish state.

The security of Syria's considerable arsenal of chemical weapons, as well as an estimated 50 tons of enriched uranium for a thwarted nuclear program, makes the Israelis extremely edgy.

Israeli leaders have warned they'll take military action if these fall into the hands of the jihadist forces fighting Assad or Hezbollah.

It's still not clear what the Israeli warplanes hit Wednesday. U.S. and Arab officials say it was probably a Lebanon-bound truck convoy carrying advanced Russian SA-17 anti-aircraft missiles to Hezbollah. Syria maintains it was a military scientific research center near Damascus, without giving any hint why that would be a target.

The fact the Israelis felt compelled to mount such a high-profile operation indicates the extent of their concern the Syrian conflict's closing in on them, enough to merit military action.

The airstrike, plus last week's deployment of two Iron Dome counter-rocket batteries to northern Israel, and a recent flurry of diplomatic activity, with Israeli Prime Minister Binyamin Netanyahu sending senior officials to Moscow and Washington, underline the Israelis' unease.

Earlier this month, the Israel army's 7th Armored Brigade, the oldest tank brigade in the military, carried out major live-fire exercises with their Merkava tanks in the disputed Golan Heights, seized from Syria in the 1967 war, to boost combat readiness.

To the south, Israel is building up its defenses along the desert border with Egypt, where in the political turmoil that's swept the Arab world for two years the Muslim Brotherhood now rules in Cairo.

The Islamists, empowered after the downfall of President Hosni Mubarak in February 2011, are questioning the historic 1979 peace treaty Egypt signed with Israel. That's been a pillar of the Jewish state's strategic security policy for more than three decades.

Cairo's loss of control of the Sinai Peninsula, where jihadist groups are mounting attacks on southern Israel, means Netanyahu has to deploy sizeable military forces there again.

On Dec. 26, the army inaugurated a new southern brigade to protect the region around the city of Eilat on the Gulf of Aqaba, Israel's only port of the Red Sea and vital for trade with Asia. It's a prime target in any future conflict with Egypt.

The formation of the Eilat Brigade, part of the 80th Division, "is an expression of our changed operational perception," regional commander Brig. Gen. Nadav Pedent said.

On Jan. 21, the military announced a new southern commander, Maj. Gen. Sami Turgeman, the former commander of the 7th Armored Brigade.

"The situation in Jordan is no more encouraging," Stratfor noted.

King Abdullah II, whose late father King Hussein signed a peace treaty with Israel in 1994, is facing rising political unrest, a consequence of the Arab Spring but heightened by his foot-dragging on promised democratic reforms and the flood of some 200,000 refugees from Syria.

This has heightened the Hashemite kingdom's perennial economic woes.

To make matters worse, more than 60 percent of Jordan's population of 6.5 million is Palestinian, long marginalized and increasingly restive.

Abdullah's nightmare is that the Israelis plan to push West Bank Palestinians to the east bank of the River Jordan and turn his resource-poor kingdom into the Palestinian state they demand.

Fallout from Syria could well ignite trouble there that will affect the Jewish state at a time when Netanyahu seems intent on driving Palestinians out of the West Bank forever.

Stratfor observed that Wednesday's airstrike may have been intended as warning to Hezbollah not to transfer weapons from Syria as the crisis there continues to degrade.

But, it said, "whatever the reason, one thing is clear: the new Israeli government facing the daunting challenge of managing multiple external threats on its borders."