"why breath a word about any of this in advance? are they nuts?" Well, it is pretty much 2x2=4 - common knowledge. As for operational details - noone's broadcating these.
If Isreal did this in the next week it would clinch the win for Bush because it would take the media focus off the economy and the situation in Iraq. Right now the election is still up in the air and I see no way that Isreal attacking Iran could hurt Bush, it could only help him and help him alot.