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It's not hard to see why Mitchell would draw hope from the analogy. By the time then-President Bill Clinton appointed him as an envoy in 1994, the Catholic "loyalists" and Protestant "unionists" had spent decades killing and maiming each other, as well as innocent civilians on both sides. Their fight was not over land, as in the Middle East, but over the status of their country: The Catholics wanted to join largely Catholic Ireland, while the Protestants  wanted to remain within the United Kingdom. But as in the Middle East, religious differences had deeply envenomed a struggle over conflicting national aspirations. As Mitchell writes in Making Peace, his account of his role in the process, "Centuries of conflict have generated hatreds that make it virtually impossible...