I think that if Israel was hit hard and was about to be overrun,then all of the Israeli nukes that we have be hearing about for years would be launched.How many do they have?Estimates range from 150 to 750.Iran would cease to exist in any meaningful way.Too bad about Syria also.
Tell you one thing, there wouldn't be an Aswan Dam any more, and that means there wouldn't be a... Cairo, IINM.