The official said the MOU is "an important contribution to getting a durable cease fire." Although it is worded in general language and short on specifics, the MOU does call for the sharing of intelligence, and it is designed to have the U.S. and Israel work with regional states to stop the flow of weapons into Gaza.
Politically, the senior official said, the hope is that this agreement will give the Israelis some assurance that Hamas will not be resupplied with weapons from Iran and other sources, and therefore it would be more likely to allow the re-opening of border crossings with Gaza.
The signing ceremony affords Rice a positive measure with which to conclude her four years as Secretary of State — and it may give Livni a political boost back home, where she is in a tight race to become Israel's next prime minister.
By CBS News State Department correspondent Charles Wolfson