In March 1964, Amer was made first vice-president to Nasser and deputy supreme commander, with the power to rule for 60 days if the president was incapacitated. Amer's distinguished career came to a sudden end after Egypt's crushing defeat by Israel in the Six-Day War of June 1967. Many historians, including Hazem Kandil, have stated that much of the responsibility for the Egyptian military's failure in the 1967 war can be laid at the feet of Amer. This is because Amer's control of the Egyptian military establishment followed in line with leader Gamal Abdel-Nasser's general policy of presenting different government institutions as fiefdoms to those most loyal to him. In addition, the proxy war Egypt (with Soviet backing) fought against the Saudis, West, and Israelis in the North Yemen Civil War (1962–1970), Nasser supporting the Yemen Arab Republic against the Western and Saudi Arabian backed Royalists, is also viewed as being key to Egypt's defeat in the 1967 Middle East war; as nearly half of the Egypt's Western-trained officer-corps (mostly in Britain at Sandhurst) was in Yemen at the time of the initial Israeli attack on Egypt.