After a drumbeat of criticism from the Bush administration and others, Newsweek magazine yesterday went beyond an apology it issued Sunday and retracted an article published May 1 that stated that American interrogators at Guantánamo Bay, Cuba, had tried to rattle Muslim detainees by flushing a Koran down the toilet. The original article was blamed for inciting widespread protests and riots in the Muslim world, where desecration of the Koran is viewed as an incendiary act, and where at least 17 people were killed in the ensuing violence. "Based on what we know now, we are retracting our original story...