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Prime Minister Benjamin Netanyahu handed U.S. Vice President Joe Biden broken glass. Netanyahu had not intended to do so, of course. He wanted to give Biden a tree-planting certificate in honor of Biden's mother. But his need to lean on the podium while addressing his guest caused the certificate's glass frame to shatter silently. When the festive moment arrived to proffer the gift to Israel's greatest friend, it turned out it was broken to pieces. The only thing the prime minister could offer the vice president was broken glass.

The moral is clear, but unforgivable. There has been tension between Washington and Jerusalem for a whole year. At a time when the two countries should be coordinated against the Iranian threat, they are having trouble...