The cause is Russia, the symptom is Iran

There is no doubt that Iran and Israel are on the path to a collision and Russia is to blame.
Once geographical separated with Jordan and Iraq between the two states Tehran’s increasing presence in Syria and support for Hezbollah in Lebanon and Hamas in Gaza has raised the ante for a direct military conflict. Hezbollah is listed by the USA as a “foreign terrorist organization” and was responsible for the 1983 attack against the MARINE barracks in Beirut.
For some years Israel has expressed concerns over Iran's missile program and nuclear ambitions. Until now the distance and time of travel from Iran ensured a small but effective strategic depth and early warning that would enable Israel to destroy missiles before they reached Israel. Lessons from the Iraq SCUD attacks in 1991 show that debris can be as dangerous as the missiles. Now Israel is growing more and more aware of the probability of a missile or even rocket attack not only from Lebanon as the PLO did prior to 1982 "Peace for Galilee" operation as well as from Syria instigated by Iran, that can target Israeli infrastructure and population centers.
Iran appears well entrenched in upholding Syrian President Bashar Assad. With Russian and Iranian support Assad is creeping towards survival and maybe even a modicum of victory in the Syrian civil war. Iran is clearly demanding a permanent presence inside Syria as the price of supporting Assad. As the spring of 2018 approaches Israel is preparing for significant strategic changes should the Iranians and Hezbollah become freed up from the Syrian civil war to attack Israel. In preventive and preemptive strikes Israel has constantly been striking positions and convoys suspected of munitions and missile deliveries in Syria.
Iran escalated this by deploying a stealth drone that violated international law by crossing into Israel's air space. Such a violation is referred to as a Casus Belli or Act of War that permits the attacked state to respond appropriately and in proportion. Israel did so. The launch site of the drone was attacked and destroyed. In doing so however an Israeli F-16 fighter jet was in turn shot down by anti-aircraft fire from inside Syria. Once again Israel responded appropriately and in proportion. Both Iran and Israel deescalated and refrained from further immediate military strikes against each other. It is not the way of the world or man to let bygones be bygones. Iran remains in Syria, Lebanon and Gaza and continues to threaten Israel. The probability of a new escalation worse than the previous is ever present.
The war of words that could led to a war of missiles was evident at a major security conference in Munich this week. Israeli Prime Minister Benjamin Netanyahu (Bibi) and Iranian Foreign Minister Javad Zarif exchanged taunts which had we been living 100 years ago would have been seen in diplomatic circles as the start of both countries arming for war and gathering alliances. Bibi told Iran that it “should not test Israel’s resolve” adding "Israel will not allow the regime to put a noose of terror around our neck,” and “we will act if necessary not just against Iran’s proxies but against Iran itself.” Zarif was flummoxed and taunted Bib's personal political problems saying he was a “cartoonish circus,” and that the "downing of the Israeli fighter jet had crumbled Israel’s invincibility."
With the cards on the table it will be either US President Trump or more likely Russian President Vladimir Putin who will play the critical role in preventing an all-out war between Israel and Iran. If the United States wishes to be an actor in the region it needs to adjust its policy to help Israel to navigate around the Russians. It is Russia that is the supplier of Iran's nuclear program and it is Russia that is ensuring the Syrian Presidents longevity. Bibi and Trump should address Putin as the source and cause of the problem and not waste time on rhetoric against Iran, Iran in Syria, and Iran in supporting Hezbollah and Hamas as it and these are only the symptoms.