From DEBKAfile, 23 Nov 2012:
Israeli Prime Minister Binyamin Netanyahu agreed to a ceasefire for halting the eight-day Israeli Gaza operation Wednesday night, Nov. 21, after President Barack Obama personally pledged to start deploying US troops in Egyptian Sinai next week, debkafile reports. ...
Obama’s pledge addressed Israel’s most pressing demand in every negotiating forum on Gaza: Operation Pillar of Cloud’s main goal was a total stoppage of the flow of Iranian arms and missiles to the Gaza Strip. They were smuggled in from Sudan and Libya through southern Egypt and Sinai. Hostilities would continue, said the prime minister, until this object was achieved...
...[Israel was] willing to take Morsi at his word [to start launching effective operations against the smugglers before the end of the month], except that...Egypt has nothing near the security and intelligence capabilities necessary for conducting such operations.
When Secretary of State Hillary Clinton arrived in Jerusalem from Bangkok Tuesday, she tried assuring Netanyahu that President Obama had decided to accelerate the construction of an elaborate US system of electronic security fences along the Suez Canal and northern Sinai. It would also cork up the Philadelphi route through which arms are smuggled into the Gaza Strip...
US security and civilian units will need to be deployed in Egyptian Sinai to man the fence system and operate it as an active counter-measure for obstructing the smuggling of Iranian weapons supplies.
The prime minister said he welcomed the president’s proposal to expedite the fence project, but it would take months to obtain Egyptian clearance. Meanwhile, the Palestinians would have plenty of time to replenish their weapons stocks after Israel’s Gaza campaign. It was therefore too soon to stop the campaign at this point or hold back a ground incursion.
Clinton was sympathetic to this argument. Soon after, President Obama was on the phone to Netanyahu with an assurance that US troops would be in place in Sinai next week, after he had obtained President Morsi’s consent for them to go into immediate action against Iranian smuggling networks.
Netanyahu responded by agreeing to a ceasefire being announced in Cairo that night by Clinton and the Egyptian foreign minister, and to holding back the thousands of Israeli reservists on standby on the Gaza border.
debkafile’s military sources report that the first air transports carrying US special forces are due to land at Sharm el Sheikh military airfield in southern Sinai in the next 48 hours and go into action against the arms smugglers without delay.
...President Morsi, by opening the Sinai door to an American troop deployment for Israel’s defense, recognizes that the US force also insures Israel against Cairo revoking or failing to honor the peace treaty Egypt signed with Israel in 1979.
...In the face of this US-Israel-Egyptian understanding, Hamas cannot credibly claim to have won its latest passage of arms with Israel or that it obtained guarantees to force Israel to end the Gaza blockade.
Indeed, Gaza’s Hamas rulers will be forced to watch as US troops in Sinai, just across its border, break up the smuggling rings filling their arsenals and most likely laying hands on the reserve stocks they maintain under the smugglers’ guard in northern Sinai, out of reach of the Israel army. This means that the blockade on Gaza has been extended and the focus of combat has switched from Gaza to the Sinai Peninsula.