Israel's fear is, if they try to take out Iran's nuclear facilities Iran will do the same to theirs using ballistic missiles. This means Israel, as well as having to attack several extremely well defended nuclear sites, would also have to take out the missile capability simultaneously. I very much doubt that would be possible given that Iran has thousands of missiles and an extremely large country to deploy them in.

I think it is nonsense to suggest Israel would strike at Iran to try and stop Obama being re-elected. In fact such an attack would probably have the opposite effect as the US becomes involved in a ME war. Americans always rally around their incumbent president in times of war. One has only to look at the war boost Bush got which earned him his second term. Prior to 911 I doubt his own mother would have voted for him.