If Israel starts a war and then comes under missile attack then the IDF can't simply hunker down and "prepare to handle an invasion". It has to go out looking for those launch sites. Here's a thought for you, Mark: what if the IDF launches just such an expeditionary force, and that expeditionary force gets taken to the cleaners? Many an army has gone out on a campaign.... and then never returned.....
UN: Gaza could be 'uninhabitable' by 2020 if trends continue (AP)
from the article: Here's why Israel must not attack Iran now