GlobalSecurity.org has an article describing the war, Suez Crisis / Sinai War / Tripartite Invasion / 1956 War (n/d; accessed 12/04/2014) The war began on October 28, when "Israeli troops crossed the frontier into the Sinai Peninsula (also seen as Sinai), allegedly to destroy the bases of Egyptian commandos. The first sign of collusion between Israel and Britain and France came on the same day when the Anglo-French ultimatum was handed to Egypt and Israel before Israel had even reached the canal." British and French forces quickly entered the action. "On November 5, 1956, the French and British took over the Suez Canal area."
The Soviet Union threatened to intervene in the war. Hersh recalls a note from Soviet Prime Minister Nikolai Bulganin warning Israel "the the Soviet Union was capable of attacking with 'remote-controlled vehicles.' There also was a threat to send troops as 'volunteers' into the Middle East."
In a position a little hard to imagine today, when the US so reflexively backs Israeli policies and American officials constantly declare the passion of their commitment to Israel, President Dwight Eisenhower opposed the British-French-Israeli invasion, thereby taking the same side on that issue as the USSR.
Hersh's footnote describes the war this way (pp. 41-2; I have added my own paragraph breaks for ease of reading):
Eisenhower's refusal to back the attack on Egypt had nothing to do with the Bulganin threat, which was analyzed at an all-night meeting at CIA headquarters and subsequently discounted as a bluff.GlobalSecurity.org relates the Eisenhower Administration's actions this way:
The Suez War was viewed by Washington not as an anti-Soviet or anti-Communist move, but as a last-ditch attempt by two powers - England and France-to stanch their continuing international decline. Eisenhower and his senior aides believed that [Egypt's] Nasser and other Third World leaders much preferred alliances with the United States rather than with the Soviets, and thus were more likely to become pro-American if the administration disassociated itself from the Middle East colonialism of England and France.
The President was distressed at the two American allies for continuing to practice what he viewed as their colonialistic policies; he also resented the obvious Israeli belief that he would pander to the American Jewish vote by endorsing the Suez War. (Eisenhower, as the French and British knew only too well, was perfectly prepared to act as a colonialist himself - as he did in ordering the CIA to help overthrow governments in Iran in 1953 and Guatemala in 1954 - to protect what he believed to be vital American interests.)
CIA officials recalled another point of White House concern in 1956: Eisenhower's realization from the secret U-2 overflights - the first U-2 spy mission had taken place a few months earlier - that Israel had purchased sixty Mystere attack aircraft from the French, and not the twenty-four they had publicly announced. No public mention was made of the larger-than-reported Israeli purchase - the new aircraft were seen on runways - since the existence of U-2 overflights was then the government's biggest national security secret. [my emphasis]
Caught off-guard by the start of hostilities, Eisenhower and Dulles took a series of steps designed to end the war quickly. Angered that his allies in London and Paris had deceived him in the collusion scheme, Eisenhower also worried that the war would drive Arab states into Soviet dependence. To stop the fighting even as British and French warplanes bombed Egyptian targets, he imposed sanctions on the colluding powers, achieved a United Nations ceasefire resolution, and organized a United Nations Emergency Force (UNEF) to disengage the combatants. After intense pressure from the Eisenhower administration, which was worried about the threat of Soviet military involvement, the European powers acceded to a cease-fire. The final evacuation took place on December 22. ...
In March 1957, Israeli troops were forced to withdraw.