Turkey's leaders have called Israel the "West's spoiled child," and the "bully" of the eastern Mediterranean. When a Tel Aviv soccer team showed up in Istanbul recently for a match, the welcome was less than warm. In September, Turkey kicked out the Israeli ambassador, suspended military and trade deals and threatened legal and naval action to challenge Israel's blockade of the Gaza Strip. As roars of approval went up around the Arab world, few noticed another announcement quietly slipped in by Ankara: Turkey had signed off on a plan to host an American X-band radar system as part of a...