First of all, the "insurgents" that are fighting against Israel are not all government-sponsored. take Syria--the government's cowering because it's powerless while the shiite group (i'm not sure) called hezbollah controls all the stuff: power plants blah blah blah. that's why foreign national leaders are urging the Syrian government to do something.

Anyhow, back to the whole nuke war or regular war: nobody wants a nuke war. That's why the Cold War was "cold". there was a story about how a Russian nuclear submarine was attacked by some Amercian warship and how in order to sanction a nuke launch, three of the ranking officers must all give their permission. One of them didn't because he knew if they fired this nuke, it'd be all out war and if the nukes themselves did not destroy everything, living creatures will succumb to "genbakusho", or radiation sickness.
i think all of the "superpowers" today have nukes and in any way, if you attack with a nuke, you are sure to end up on the receiving end of it sooner or later.
whether wars are fought for ideals or age-old hatred or other more private interests, i think there are enough people with enough sense to see that wiping each other out isn't a really viable solution because admit it, we all want life...right?