Peace between Israel and Egypt was threatened late last week after a cross-border terrorist attack between the two countries prompted Israeli defense forces to fire at Egypt, killing three Egyptian officers.  The killings spurred a diplomatic crisis. Egypt announced that it would recall its ambassador from Tel Aviv, Israeli defense minister Ehud Barak broke the Sabbath to issue a rare statement of regret for the deaths, and thousands of Egyptians protested outside the Israeli embassy in Cairo.  The crisis is the sharpest signal yet that the amicable relationship between Israel and Egypt has changed. Aaron David Miller,  former Middle East adviser to both Republican and Democratic secretaries of state, and the author of "The Much Too Promised Land: America's Elusive Search for Arab-Israeli Peace,"  discusses these recent events. Miller's new book, "Can America Have Another Great President?" will be published by Bantam Books in 2012.