Can't Israel annihilate Iran in just a jiffy?

I don't know if you've been following the recent news about what is going on in the Middle East or not, but the Israelis carried out an assassination plot, almost two weeks ago, against a Hezbollah military leader in Beirut, and also against a major Hamas leader, Esmaeil Haniye, in Tehran who was there to celebrate the inauguration of the new Iranian President. Iran has vowed revenge, because Israel has clearly violated the international law and orchestrated an act of terror inside the Iranian borders, right in the capital city. The US and Mossad have gathered intelligence about the recent military movements and deployments inside Iran and other parts of the region which shows the Iranians and their allies are preparing for a large-scale attack. While there is no information on the actual scale and the timing of the attacks, the US, some European countries and some Arab states in the region who seem to be supportive of Israel are preparing an unprecedented defensive circle to foil the upcoming missile and drone attacks, that are supposed to be launched from several fronts.

Iranians claim this attack will inflict such heavy damage on Israel that they will be forced to agree to a deal under terms offered by the resistance, and end the war in Gaza in disgrace. But if the Israelis make any stupid mistake to go another step further towards a counter-attack, Iranians have announced, they are not afraid of an all-out war, that might severely entangle the US army and other countries in the region, and greatly impact the world by driving up the oil price. Let's see what happens.

But this is the question. Why wouldn't Israel act on its own, and why would they need such huge military assistance from its allies, if they could just (at least that's what some Israel's supporters claim) annihilate Iran in a jiffy? Opinions about other aspects of this topic are also welcome.

Can't Israel annihilate Iran in just a jiffy?
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