The consequences of an Israeli strike on Iran's nuclear programs can't be evaded, just managed should it come to that, not unlikely, like it or not.
As to the consequences, Iran may well try to shut the Straits of Hormuz. Fortunately, that can be managed by placing enough forces in theater, if only at Diego Garcia, the one place where host state objections won't matter.
Placing such forces beforehand might be the best way to prevent the eventuality of both an Israeli strike and the consequences of Iran's response, because it would deny them a theory of victory, especially if the Tridents converted to missile subs were all in range. With sufficient carrier forces, probably three, that is enough air cover to allow for long range airstrikes and bombardments from the Tridents to take out Iran's missiles on the Gulf, and bombard land forces that may well try to seize islands as part of any potential denial strategy to the Gulf. That latter possibility would also indicate that an MEF probably would be wise to have close at hand as well, in addition to lasing targets on Iran's coast.
Of course, it would be better to negotiate a solution rather than launch more than 1,000 PGM strikes, that risk Russian and Chinese objections, but that clock is probably ticking too, unless you think Israel is fundamentally bluffing, and just want to wait and see what happens, and surge forces as quickly as possible in the event that consequence management becomes an issue. A wild card of course is what Assad does as well, since if nothing else he can fire a significant number of missiles, independent of a likely Hizbollah retaliation too.
As to what diplomacy might could do, if the Palestinian situation won't solve everything, it might provide Iran cover to back down, if that's a big if.
Some people have thought that as part of a general settlement that would make sense, as well as providing Israel the same guarantee with nuclear deterrence as with Japan, including tripwire forces as the credibility guarantee as part of securing the Jordan River Valley, something any feasible Israeli government would insist on, along with Right of Return to the Territories only, and 1967 Lite between the four per cent of Clinton and the five per cent of Netanyahu. Anything else as to the UN report on "illegal settlements" is delusional in character, as well as being pointlessly provocative. As to paying for such a thing, the Gulf Arabs Saudi Arabia included care rather a lot about a certain mosque, unfortunately the site of the Second Temple as well. Whatever the status of East Jerusalem, already dangerously close to mutually incompatible desires, some legal fiction, preferably guaranteed by Quartet patrols, plus Israel and Jordan-Arabs, in return for Saud money at the level of the current Israeli aid package for ten years to construct infrastructure in the Territories for a new state, tunnels included more than likely, would be a reasonable settlement that if not formally tied to an Iranian settlement, might help induce that.
Time however is more than likely not an ally, and those who encourage the Palestinians to ask than more than is militarily feasible in any universe are not really their friends in the long run, whatever tragedy one might see in their repeated gambles for a full loaf, instead of half of one.
But as to Iran, that is unlikely to be evaded forever.