In all honesty, I don't know - I would guess it would depend on a lot of things, but primarily the perceived level of the Iranian threat and the military assessment of whether such a strike would be a) viable and b) effective.
All that follows is speculation based on the military aspect of any such strike. I don't doubt the Israeli will or ability but I do have grave doubts about about some specific and difficult problems within the situation that render the structure of the IDF incapable of performing the mission because of them.
We're all familiar with the famous Osirik strike by the IDF in which Iraq's nuclear capability was taken out in one fell swoop. Iraq had helpfully grouped all of its nuclear facilities in one area and the Israelis destroyed them. They did the same thing to a Syrian attempt last year.
So, as many ask, why can't they do the same thing to Iran. Primarily because Iran took note of what happened in Iraq and purposely spread its nuclear facilities all around its country. It eliminated the possibility of a single strike crippling its efforts toward realizing its nuclear goals. As you can see on the map, hitting the key Iranian nuclear sites would require a bombing campaign, not just a single strike.
The recent revelation also points to another probability. It appears that Iran is building redundancy into their nuclear facilities. Nothing says there are only two enrichment facilities. In fact the existence of two argues that there may be more that haven't been discovered yet. But it does make the point that even if key known facilities are hit and destroyed in Iran, there is absolutely no assurance that those strikes will have destroyed Iran's capability.
Then there's the distance involved. Even with Saudi Arabia supposedly telling Israel it will turn a blind eye to their incursions into Saudi airspace in order to hit Iran, we're talking about a limited ability to do so without refueling. Israel has some converted Boeing 707s it uses for the job but certainly not enough to support a campaign of this size. And while it has developed technology with which it can mount external fuel tanks to weapons stations, that obviously trades fuel for weaponry, meaning more aircraft will be necessary to do the job.
That limitation, coupled with the way Iran has spread its nuclear facilities out, means Israel would have to commit to a bombing campaign as I mentioned earlier. Several hundred sorties are likely to be necessary to degrade all the facilities necessary to neutralize Iran's nuclear capabilities. I say several hundred because part of getting the strike aircraft to their targets will entail other aircraft flying air defense suppression missions. What we call "wild weasel" missions would require other aircraft to clear a path for the strike mission by taking out Iranian air defense radar capability prior to the insertion of the strike package.
All of that requires tremendous coordination. Once the first strike goes in, whether successful or not, the defense level of the Iranians will rise to its highest levels. At that point, follow on strikes would find getting to their targets unscathed to be a much more difficult job. And, of course, there's the necessity of staging search and rescue operations for downed pilots. Given the countries the IDF would have to fly over, even with permission, staging SAR would be next to impossible.
So, in my opinion, the combination of distance, the requirement of multiple sorties against spread out and redundant Iranian facilities and no assurance of success argues pretty strongly against an Israeli military strike. That's not to say that the Israelis won't figure out a way to do it, do it well and survive it. They've surprised us before, but I'd suggest the odds aren't in their favor.
Of course, last but not least, any strike by Israel, whether or not successful, is an act of war which Iran will seize upon to not only step up its proxy war against Israel, but use as a basis for a direct attack on that nation at a future time and place of its choosing. The question will be when, not if and it will certainly include speculation as to the type of weaponry Iran will use to reap its revenge.
I listened to Israeli PM Benjamin Netanyahu address the UN this past week. I heard the palpable disgust he has for the members of that body and their refusal to act to thwart Iran's nuclear threat. But I also heard a little pleading in there as I think Israel has come to the realization that this is a situation in which they don't have the military capacity to take care of business. He was quietly pleading with the US and the rest of the world to actually step-up and prevent a possible nuclear catastrophe that could, as Iran has claimed to desire, wipe his country from the map. Israel has come to the realization that perhaps their audacity and bravery won't be enough this time. They may need some help. And with the revelation that Iran now has solid fuel technology for their long range missiles, they may need help very quickly.
Where it will come from, unfortunately, is not evident to me or to them. They may end up having to take a short-term, high risk chance and live with the long-term no-win consequences.