The stated reason the ALP has punished floor-crossers in the past is that their strength is in their solidarity with each other. Picking and choosing when to enforce party discipline based on the circumstances is an interesting move. I agree the PM has many things to consider. He's in a position his political opponents both on the left and the right don't have to worry about on Israel - the Greens are united on one view and the Liberals are united on a different view. The ALP has both views inside the party.