For Israel to be successful they would need a joint U.S. operation. However, this would play extremely bad in the Arab / Muslim world.....thus offsetting many of our recent gains.
If and when Iran is taken on via a military option it will come from a mostly U.S. strike (with no direct Israel involvement) - A few NATO Nations will be along as well.
The current situation leaves no real good military option however. But the clock is ticking down until we'll have to play the hand that is dealt us.
That time is not here yet though.