I've heard former US Ambassador Edward Peck before. He's a relatively clear thinker. He can also speak on his feet, as you will no doubt be able to tell from this segment from Democracy Now.
He hit the main point, which is that Israel has no legal right under International Law to be doing what it's doing vis-a-vis Gaza, or the West Bank for that matter.
Everything Israel has done to appropriate land at least since 1948 has been illegal. There was much terrorism and ethnic cleansing. Even some major swathes of lands that some Jewish organizations supposedly purchased before 1948 were purchased from people with dubious titles. Regardless, the British Empire never had the right to grant the Zionists any of the Palestinians' lands. Besides, the Zionists failed to adhere to the terms of the Balfour Declaration anyway, which called for equal, non-prejudicial treatment of the Palestinians, something Israel has never honored. Also, it is my understanding that the Security Council never finalized the United Nations vote for an independent Israel but rather Israel simply declared itself independent and the powers did nothing to stop it. Truman claimed to have been lulled by the Israelis, something he came to regret. Lastly, Israel started the wars in which it claims to have conquered lands that it therefore doesn't have to return. The truth is that such land can only be claimed under the law in cases where Israel did not start the wars and even then, there are qualifiers.