Has nothing to do with getting elected again. Has everything to do with leadership, and as they say 'he ain't got none!'
For now.
Further, with nuclear weapons and still the best conventional forces in the region, Israel frankly isn't going to ask us to protect it beyond some military cooperation. If anything, Bush is warning Iran and preparing for a possible good excuse to attack Iran. Far from not acting, Bush will act against Iran and polls already show majorities support such action. Most Americans say the threat from Iran is far greater than it was from Iraq.