in 1957 that any closure of the Straits would be considered an act of war, or justification for war, but Nasser closed the Straits to Israeli shipping on 22–23 May. After the war, U.S. President Lyndon Johnson commented: On 30 May, Jordan and Egypt signed a defence pact. The following day, at Jordan's invitation, the Iraqi army began deploying troops and armoured units in Jordan. They were later reinforced by an Egyptian contingent. On 1 June, Israel formed a National Unity Government by widening its cabinet, and on 4 June the decision was made to go to war. The next morning, Israel launched Operation Focus, a large-scale, surprise air strike that launched the Six-Day War. Military preparation Before the war, Israeli pilots and ground crews had trained extensively in rapid refitting of aircraft returning from sorties, enabling a single aircraft to sortie up to four times a day, as opposed to the norm in Arab air forces of one or two sorties per day. This enabled the Israeli Air Force (IAF) to send several attack waves against Egyptian airfields on the first day of the war, overwhelming the Egyptian Air Force and allowed it to knock out other Arab air forces on the same day. This has contributed to the Arab belief that the IAF was helped by foreign air forces (see Controversies relating to the Six-Day War). Pilots were extensively schooled about their targets, were forced to memorise every single detail, and rehearsed the operation multiple times on dummy runways in total secrecy. The Egyptians had constructed fortified defences in the Sinai. These designs were based on the assumption that an attack would come along the few roads leading through the desert, rather than through the difficult desert terrain. The Israelis chose not to risk attacking the Egyptian defences head-on, and instead surprised them from an unexpected direction. James Reston, writing in The New York Times on 23 May 1967, noted, "In; discipline, training, morale, equipment and general competence his [Nasser's] army and the other Arab forces, without the direct assistance of the Soviet Union, are no match for the Israelis. ... Even with 50,000 troops and the best of his generals and air force in Yemen, he has not been able to work his way in that small and primitive country, and even his effort to help the Congo rebels was a flop." On the eve of the