Working in the National Security Council in the George W. Bush White House, I dealt constantly with Prime Ministers Ariel Sharon and Ehud Olmert and their top staffs. They understood that Bush was committed to Israel's security, and that fact changed their world. It meant they could be sure we would always block assaults on Israel in the United Nations - and would do so willingly, happily, not as some kind of terrible burden to American diplomacy. They could be sure that if the president gave his word, he would keep it; there were no red lines drawn and then withdrawn. We could discuss every option for peace and for the use of military power openly and in full confidence, because they understood that the United States viewed Israel as a valuable ally whose security mattered to us.