The Government of Israel should attack and remove Iran’s nuclear facilities if the Iranians development of nuclear weapons is imminent. It has every right to do so and would be derelict in it’s duty to the Israeli people if it didn’t. Iran is developing nuclear weapons for one reason and one reason only: to use them against Israel, which they would of course do if they were in their possession. A preemptive strike by the Israelis would be necessary to prevent a nuclear attack on them.
Of course every measure should be taken to prevent Iran from acquiring nuclear weapons in the first place. If all else fails however Israel has no choice but to go it alone, with or without approval from the United States.
In the end Israel can depend only on itself and expecting the U.S. to defend it militarily could be suicidal. So could holding back while America dithered, which is entirely possible given President Obama’s mushy thinking in foreign affairs to date and seeming inability to prevent behaviour by various regimes that is potentially harmful to the United States and/or it’s allies. If Obama came to the conclusion that jettisoning Israel would somehow be in his country’s best interests or fit into some sort of personal ideology he would do so, regardless of anything he has said or commitments he has made.
The Israelis are well aware of all this of course. They would attack as a last resort with the greatest reluctance, but attack they would. Rightly so. any other country would do the same under similiar circumstances.
And yes, the Iranians would have no one to blame except themselves.