Here is a very interesting article by Le Monde Diplomatique on Israel's offensive in Gaza. Its premise is that Israel's actions constitute clear violations of the Geneva Convention (e.g. its prohibition to attack, destroy, remove or render useless objects indispensable to the survival of the civilian population and to starve the population) and therefore constitute war crimes. The article also talks about how the kidnapping of the soldier was only an excuse and that Israel had prepared this offensive even before Hamas won the election.
It's worth reading.