In the early hours of Thursday morning, Israeli forces conducted what was the largest attack on Syrian territory since the official end of the Yom Kippur War in 1974. The airstrikes were in response to what they said was an Iranian rocket attack on the Israeli-occupied Golan heights.
This escalation is only the second time that Iran has been accused of directly targeting Israeli soil, following a failed drone attack in February. And it comes just days after US President Donald Trump's decision to walk away from the landmark nuclear deal agreed with Iran in 2015 -- pouring fuel onto a raging fire.
Over the past six years, Israel has grown increasingly concerned that Iran and its allies -- above all the heavily armed Lebanese militant group Hezbollah -- are establishing a large, permanent presence in southern Syria. This would allow them to attack Israel not only from Lebanese soil -- where Israel waged a destructive war with Hezbollah in 2006 -- but also from across the border.
In response, Israel has conducted numerous airstrikes in Syria over the past six years.
One of the largest of these, less than two weeks ago, may have killed Iranian personnel, causing tension to spike.
It was almost certainly in retaliation for that episode -- and other Israeli attacks in April -- that Iran's Quds force, an elite unit of the Revolutionary Guards, sent rocket fire in Israel's direction on Wednesday night. In short, both Israel and Iran have deliberately escalated the conflict over the past month.
If Iran continues to launch direct attacks on Israel from Syrian soil, Israel is likely to retaliate with ever-larger airstrikes.
Israel's calculation is threefold. One is that the Syrian government, threatened with the prospect of a regime-shaking Israeli attack, has an incentive to try to restrain Iran's activities. Israeli ministers have issued explicit warnings to Damascus several times in recent months, and hit the regime's air defense systems in Thursday's strikes.
Another is that the US would certainly step in were Iran to cross red lines, such as striking major Israeli cities with longer-range missiles.
The third is that Russia, which itself has a large military presence in Syria, will continue to indulge Israel's repeated incursions, preferring diplomatic rebukes to military confrontation.
Not only did Israel forewarn Russia about its latest strikes, but they came hours after Israeli Prime Minister Benjamin Netanyahu appeared alongside his Russian counterpart Vladimir Putin at a parade in Moscow.
Israel is signaling to Iran that it cannot rely on Russian protection. With an American backstop, Israel can act relatively freely. With uncertain Russian support, Iran must be more careful.
However, Russia's position could change. If Israeli actions appear to threaten the stability of the Syrian regime, putting Russia's strategic position at risk, then Moscow might be willing to take a firmer stand against Israel. This, in turn, would increase the risk of a standoff between two big powers: the United States and Russia.
The wider context of rising regional tensions and a crumbling nuclear deal is important. Hezbollah's strong showing in Lebanon's parliamentary election last week will have reinforced Israel's concerns over the expansion of Iranian power.
For Iran's part, the growing convergence between the Arab monarchies, Israel, and the US -- and the rise of American officials with visceral hostility to Tehran -- increases the importance of preserving leverage against these adversaries not only in Syria and Lebanon, but also in Iraq, Yemen and elsewhere.
If America's withdrawal from the nuclear deal provokes Iran to expand its nuclear program once more, the risk of Israeli or American attacks on Iran's nuclear facilities will start growing, as it did between 2011 and 2013.
Iran, much weaker in conventional military terms, will seek to develop and demonstrate asymmetric ways to deter such an attack.
These could include terrorist attacks on Israeli interests, cyberattacks against Arab and American targets and the use of Shia militia to pressure American forces in Iraq and Syria -- all of which have been seen in the past several years.
In other words, regional conflict and a renewed nuclear crisis are likely to become intertwined, each fueling the other. The Iran-Israel confrontation in the past few days is likely to presage a more unstable and violent period in the Middle East.
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