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As befits the son of a historian, Benjamin Netanyahu loads his speeches with references to the past. He talks about 3,000 years of Jewish history in Jerusalem; he conjures up the Holocaust when he discusses Iran's nuclear program; he recalls the Arab rejection of partitioning Palestine in 1947 to show who's at fault in the Israeli-Palestinian conflict.

Yet the prime minister's short-term memory seems to be vanishing. Otherwise, it's hard to understand his comments to a Knesset panel this week, explaining his decision to ease the Israeli siege on Gaza. The new policy of allowing free import of civilian goods, he said, was entirely in Israel's...