What reaction by Israel wouldn't be disproportionate?

'Israel is bigger than Gaza and the West Bank, but it is smaller than almost everywhere else. Less than a century old, it is a democracy surrounded by hostile nations and under permanent attack by terrorists who wish to see it wiped from the surface of the Earth. What is a "proportionate" response to a hydra-like enemy who sees the Final Solution as work in progress? All terrorism aimed at Israel is genocidal in spirit. What would a "proportionate" response to that ambition look like?'

More common sense from Matthew d'Ancona in the usually rather anti Israel London Evening Standard here
http://www.standard.co.uk/comment/matthew-dancona-cameron-is-right-not-to-put-israel-on-the-naughty-step-9651315.html