Secretary of State John Kerry over the weekend assembled an impressive array of allies willing to take part in what President Barack Obama’s administration is now calling its “war” on the ultraviolent Islamist group ISIS. 

In addition to such NATO allies as Great Britain, Germany, France and Italy, several Arab nations, including Jordan, Saudi Arabia and the United Arab Emirates, have joined the nations arrayed against the terrorist group that last week, in cold blood, beheaded another foreign national, David Haines, a British humanitarian aid worker.  British Prime Minister David Cameron described the latest killing as “an act of pure evil” and vowed to bring those responsible to justice.

As the alliance builds, however, an open question remains about what the world, and the United States in particular, will do in defense of the State of Israel. Of particular concern amid the growing chaos is Israel’s border with its northern neighbor, Syria. The number of parties and interests involved, none of whom have any love lost for Israel, is staggering.

ISIS is a Sunni Islamist movement, as is much of the Syrian army. The Lebanon-based Hezbollah, which maintains a presence in Syria near the border, is of the Shia sect, thus making the two groups sworn enemies. Add to that the utter devastation and anarchy reaped by Syrian President Bashar al-Assad and a number of other splinter groups, and the border has almost overnight gone from being relatively secure to fraught with peril.

Since the disengagement agreements between Israel and Syria negotiated by then-Secretary of State Henry Kissinger after the 1973 Yom Kippur War, the Golan Heights border between Israel and Syria has been mostly quiet. A notable exception was a brief period at the start of the Arab Spring rebellion against the Assad regime.

Yet as horrific a leader as he’s been of his own country, neither Assad nor his father generally targeted the Golan Heights for either frequent or meaningful attacks upon Israel. United Nations peacekeeping forces were stationed on the Golan Heights-Israel border in 1973 to assure stability and security.

That quiet border is now directly threatened by the aggressive actions of ISIS, which is gaining ground near that border, and others.  Already, a rival terrorist group affiliated with al-Qaida has held United Nations peacekeeping troops from Fiji and the Philippines hostage for several days.

As the U.N. peacekeepers are driven out of the area, or if they are rendered useless by ISIS aggression, Israel’s northern border would be in grave danger of being invaded by fanatic ISIS fighters who have already taken over one-third of Iraq and a large swath of Syrian territory.  Moreover, though rival Islamist factions may go head to head with one another, there is no assurance they won’t come after their common enemy, Israel, if not in tandem, then separately.

Obama, in his address to the nation last week on his efforts to destroy ISIS, said he “would not hesitate” to launch airstrikes against ISIS targets in Syria along with those he has already authorized in Iraq.

So what precisely will happen if ISIS or others directly invade northern Israel across Syria’s border at the Golan Heights?  It was just such an invasion by the regular Syrian Army that caught Israel off guard during the 1973 Yom Kippur War. Surely, there will be no surprises here – the drama is unfolding as Israel and the rest of us look on.

The leadership of America is utterly crucial in this endeavor, because there’s not a great assurance that the rest of the coalition being stitched together in opposition to ISIS will come along in defense and protection of Israel.

Yes, Israel has more sophisticated military, intelligence and weapon systems than many, if not all, of its neighbors in the Middle East. But the cost in lives and dollars of a sustained assault on either one or multiple borders is incalculable. Without the partnership of at least the U.S., if not others, the peril for Israel will be worse than any number of low-tech rockets flung from across the Gaza border by Hamas.

The temptation by the Arab nations to sacrifice Israel’s security in the fight against ISIS will be huge. The ability to build coalitions with other Western countries to defend Israel will be challenged by the mixed world reaction to the Gaza war. In this environment, America must show just as much leadership to its support and defense of Israel as it is bringing to the ISIS confrontation.

Anything less would be unconscionable and would put the safety and security of Israel at risk. 

That cannot and must not happen.