WASHINGTON - U.S. Secretary of State Condoleezza Rice departs for the Middle East Sunday facing one of the sternest challenges of her diplomatic career.

For decades, it has been an unwritten rule of U.S. diplomacy that secretaries of State should not risk their reputations by heading into a Middle East war zone without reasonable assurance that they can emerge with a deal.

In this case, in addition to the fighting in Lebanon, the Bush administration is struggling to meet the tests of two other regional hotspots, Iraq and Iran. While trying to make progress on Lebanon, it can't afford to look ineffective or to alienate regional allies by giving the impression that Rice is buying time for continued Israeli military operations.

Rice appears to be hoping it will be sufficient to show determination and make small steps toward a deal, analysts say. “I know there are no answers that are easy, nor are there any quick fixes,” she said Friday in announcing the trip.