Like many in Washington, Barack Obama is running as fast as he can from the authors of a controversial new book on U.S.-Israeli politics. And in doing so, he's taking a distinctly different path than one of his highest-profile supporters in the foreign policy establishment, Zbigniew Brzezinski.After being alerted by a reporter for the New York Sun, the Obama campaign raced yesterday to take down a small ad for the campaign's Web site that appeared as one of several "sponsored links" on the Amazon.com page for "The Israel Lobby and U.S. Foreign Policy" by John Mearsheimer, a political scientist at the University of Chicago, and Stephen Walt, a professor at Harvard University's John F. Kennedy School of Government. The book argues that a highly influential assortment of pro-Israeli politicians, journalists and academics have succeeded in pushing U.S. policy in the Middle East in directions that do not necessarily serve America's best interests. And, like an article by the authors that appeared last year, the book has caused a considerable stir - critics have accused the authors of anti-Semitism, admirers have praised them for needed candor, and several institutions and organizations have turned down or canceled appearances by the authors, including the Graduate Center at the City University of New York and, the Chicago Council on Global Affairs.