"War is a matter of life and death of the state; it must be pondered deeply." Sun Tzu.
It's pretty obvious that there's a lot of tension over what to do next with Iran and it's nuclear program.
It's worth prefacing the analysis that follows by stating that, first, the author thinks that the Iranian nuclear program is indeed a nuclear weapons program, if more than likely for now of a "bomb in the basment type."
What that "bomb in a basement type" means is that Iran wishes to have the appearance of possibly having a nuclear weapon, without all the opprobrium that comes with that, while though it prepares a "breakout" strategy to mate such weapons to the Shahab 3 missile in the long run, if and only if that seems wise to do.
That doesn't mean Iran would attack Israel or the U.S. with nuclear weapons, just that at a minimum, it would like to alter the balance of power by acquiring that capability, not a trivial thing to do.
The bomb in the basement strategy is not dissimilar to our use of "calculated ambiguity" in nuclear deterrence threats. Many for example see Japan's possession of more than 1,000 kilograms of plutonium in that light, in which there would exist an impenetrable (culture) Japanese military intelligence unit that could detonate a simple weapon on short notice, should Japan ever be abandoned by the United States; just in case.
Other than that, nothing.
If China for example should threaten them absent U.S. nuclear deterrent protection, you would want to be able to have some test too, if of course that is the case, it's just that many think it is the case, if it's not polite to say much about it.
Moreover, the more Iran is perceived as having a nuclear weapon, the more free it is to pursue desired foreign policy objectives. It hasn't done that yet, but at some point would be able to say, "Maybe you don't want to attack Hizballah and find out the consequences." In escalation from that, detonating a weapon would be the signal that the threat was actual, not hypothetical, although doing so could trigger a nuclear war.
As to Israeli concerns about Iran's program, it is also possible that Iran could want to someday detonate a nuclear weapon on Israeli territory, and hope it couldn't be attributed to it.
However, to take such a step would be the biggest gamble in military history, because there is no way to know if Israel wouldn't just assume it was Iran, and then efface it from the Earth. That scenario therefore might be a little overbought by Israeli and other security analysts, as then one would have to believe that the Iranians were totally crazy, instead of semi-crazy.
They have already run high risks, however, to this point, and moreover, have cast the identity of their whole regime in hostility to America and Israel in order to rationalize what has become a fairly corrupt and incompetent rule of the clerics.
That's also easy to say from a safe distance, "Don't worry about the possibility of asymmetric threats of nuclear use, "as to not worry too much about the unattributable/asymmetric threat.
If the Israelis feel that's not something they can live with, the author would understand that, if these are the consequences below that lead one to consider a unilateral American strike, and its consequences.
As to the consequences of an Israeli strike, because of distance, the Israelis will not be able to destroy Iran's ability to attack Western interests in the Persian Gulf. The strike itself is a doable stretch for the Israeli Defense Forces. It's also not risk free, as to putting a sizable portion of the IDF Air Forces on a probably known path over Arab territory, or even Turkish territory, if, Israel's nuclear deterrent presumably provides some protection against any "air defense bait and switch."
In any event, if Iran launches counter-attacks at Western interests in the Persian Gulf in response to an Israeli strike, then we are in that conflict.
One might be safe in assuming Iran would respond negatively to having its nuclear program bombarded by Israel using American made weapons, , hence the argument for considering a unilateral American strike, which would be understood as something of a proxy for Israel, but also more than that.
The reason it would be understood as more than that is that any doubts about American intentions to use force in the dispute as it escalated would of course be over; and then you have the consequences to consider.
If the hypothetical raids were large enough, it is likely that they would succeed in taking down Iran's ability to interfere with naval shipping in the Persian Gulf, although probably not without substantial loss of American lives, and especially Iranian combatant and non-combatant lives.
The reason for caring about the latter, beyond basic human concerns, is the reaction of the Muslim world.
To attack an Islamic country, even one that is a Shia outcast in many ways, is not a trivial matter, especially given the presence of American troops in Afghanistan.
One could predict with a high level of probability that American soldiers would die in Afghanistan because of a strike on Iran, if we can't be driven in disorder from the country and/or defeated militarily, as we have too much firepower. In the worst case, i.e. asked to leave, and then denied egress through Russia, China, or Pakistan, we can evacuate through Iran, just devastating the country as we proceed if need be to deter partisan attacks. That's truly the worst case, and not very likely.
On the other hand, Russian and Chinese objections to any American raid on Iran have to be taken very seriously.
China is now Iran's biggest investor and trading partner. Both China and Russia use Iran not only in energy markets, but also more fundamentally in order to lever against American dominance in the international system.
North Korea does the same thing, in which, and this is politically incorrect to say, Jewish influence in the United States is so patently obvious overseas, that to strike at Jews is perceived as damaging American power.
An annecdote will tell the tale.
When at SAIS, one of my first conversations was with a Frenchman, from the Ecole, not a redneck like Le Pen, to put it mildly.
He said to me, and from the Ecole Polytechnique:
"Why do you let the Jews run everything?"
Now, being from Alabama, and being the one usually suspected of being the at best closet racist, I tried to dissuade him of that idea, mainly in terms of what is the case, and which African-American Thomas Sowell pointed out, which is that ethnic groups have differential levels of success economically on average because of their culture in no small measure, and that this is always true.
Some groups do better than average, like Northeast Asians in America or Chinese in Malaysia, and some do worse than average; here in America, the Jews have done pretty well, to put it mildly.
Thus, to strike at Jewish interests is perceived in some quarters overseas as the obvious way to strike at America, in terms of its power elite's interests.
That doesn't mean you just salute what comes up the flagpole because its kosher so to speak, but, don't assume that just because someone is messing with Israel doesn't mean it's not really about you too.
In the end, if Russia and China want to fight a Great Power War, they can find a way to do so, and if they did that by encouraging Iran, well, we didn't cause that problem, and so destroying their nuclear sites unilaterally might make sense, or might make Iran back down right now.
On the other hand, since that is doing a favor in many ways for both Arabs and Israels, and since running such risks as it is is not trivial, it would seem obvious that encouraging a moderation in demands in the Palestinian situation, on both sides, might be the best way to both repay risks run, and most importantly avoid war in the first place by giving Russia, China, and especially Iran something to show for the whole exercise, potentially important, since pride and its wounding often drives war.