The entire world watched as President Donald Trump announced America's exit from the Iran nuclear deal, and his re-imposition of the full range of sanctions on Iran.

While the British, French, and German governments made clear their strong preference that the U.S. maintain the JCPOA, Prime Minister Benjamin Netanyahu was not shy in his efforts to convince the White House of the wisdom of his opposite position.

Netanyahu’s unusual English-language prime time presentation on Israeli television last week of the intelligence collected by Israel about Iran’s previous efforts to build a nuclear weapon was almost certainly aimed at Trump, either in an effort to convince him to exit the deal, or to provide cover for him to do so.

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But while Netanyahu is as certain as ever in his opposition to the JCPOA, convinced that it is paving Iran’s eventual path to a bomb while providing oxygen to the Tehran regime for its continued survival, he may be ignoring an overlooked aspect of the Iran deal’s dynamics - and the way in which it has, until now, prevented a full-on Israeli-Iranian war in Syria.

The Iran deal met with intense opposition in Israel from the moment of its conception through to its negotiation and implementation in the summer of 2015. Israeli politicians and security officials across the board believed it to be a naïve and ill-conceived idea, and Israeli opposition to the agreement reached an apex with Netanyahu’s controversial March 2015 speech before the U.S. Congress.

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The debate currently taking place in Israel over whether it would be better for Israel’s security for the deal to remain in place – notwithstanding the original opposition to it – or for the U.S. to reimpose sanctions and risk Iran restarting its nuclear program, while trying to force Iran into better terms, has focused entirely on Iranian nuclear activities.

Yet there is another dimension to this calculus that must be taken into consideration and that is ancillary to Iran’s nuclear program itself.

The largest and most imminent threat to Israel’s security right now is not a nuclear Iran, but Iranian activity in Syria.

In recent months, Israel and Iran for the first time in their history engaged in direct hostilities, rather than Israel responding to attacks from Iranian proxies. In February, Israel shot down an armed Iranian drone that had penetrated Israeli airspace and attacked Iran’s drone command center at the T-4 airbase in Syria in response.

In early April, Israel again struck the airbase, killing seven Iranian Revolutionary Guard Corps soldiers, and on April 29 missile strikes believed to have been carried out by Israel destroyed weapons depots at two more Iranian-controlled bases in Syria.

Open gallery view A Ghadr H surface-to-surface ballistic missile is displayed by Iran's Revolutionary Guard in an annual pro-Palestinian rally marking Al-Quds (Jerusalem) Day, in Tehran, Iran. June 23, 2017 Credit: Vahid Salemi/AP

These strikes have come amidst unswerving statements by the Israeli government that it will continue to enforce its two red lines in Syria, and escalating concern over the possibility of an Iranian response igniting a war on Israel’s northern front.

Yet for all of the warnings about Iranian retaliation in the face of Israel’s larger and more public strikes on Iranian positions, Israel is still waiting with bated breath for an Iranian response.

While part of Iran’s reticence is undoubtedly a result of Israeli military superiority and successful deterrence, part is also due to the looming nuclear deal deadline.

The Iranian government has been crystal clear that it wants the Iran deal to remain in place, for obvious reasons. It has been a lifeline for a faltering Iranian economy and allowed the regime some escape from its diplomatic isolation.

So long as Iran itself remains in the deal and no evidence exists that it is violating the core provisions that prevent it from pursuing a nuclear weapons program – and the evidence Israel revealed last week pertained to Iran lying about its previous activities but was silent on whether it is doing so now – the Iranian government will be able to continue on its current path.

The one thing that could upset this balance is Iran launching a war against Israel, either directly or by activating Hezbollah and its hundreds of thousands of guided missiles pointed at Israeli targets from Lebanon.

Should this happen, it will certainly provoke a severe diplomatic response from the U.S. but will also make it eminently more difficult for the E3 powers – Britain, France, and Germany – to argue that Iran is behaving responsibly and that it is worth continuing to engage with the regime.

Iran does not want to give any of the countries on the other side of the Iran deal an excuse to exit it. The best excuse it could provide would be a war that targets Israeli population centers and infrastructure, decimating the north and sending millions of Israelis into bomb shelters.

Israel has been making a consistent case that the Iran deal is bad for its security on the nuclear front, but there is a risk that if the Iran deal collapses entirely, it will create a more immediate and proximate threat for Israel to deal with.

The Iran deal is keeping Iran in check from responding to repeated Israeli strikes on its interests in Syria.

Open gallery view Missile contrails seen in Israel during overnight air strikes in Syria

Trump took on Netanyahu’s exhortations to rectify what the prime minister views as a grave American mistake that made Israel more vulnerable. But the U.S. president may just have ended up creating a new vulnerability for Israel, by removing a key restraint on Iran’s conventional forces.

The Iran deal was singularly focused on Iran’s nuclear program, but it unleashed a set of other incentives impacting Iran’s regional behavior, creating space for Iranian adventurism in some ways and constraining it in others.

Netanyahu's concern now will be the downstream effects of America's exit from the deal. He was concerned about Iran's nuclear variable, a threat that will only impact sometime in the future, but that will have to be set aside; Trump's exit could have escalated a far more immediate impact on Israel's security - conventional conflict with Iran in Syria.

Michael J. Koplow is the policy director of the Israel Policy Forum. Twitter: @mkoplow