Schlesinger had an abiding interest in strategic theory, but he also had to deal with a succession of immediate crises that tested his administrative and political skills. In October 1973, three months after he took office, Arab countries launched a surprise attack on Israel and started the Yom Kippur War. A few days after the war started, with Israel not faring as well as expected militarily, the Soviets resupplying some Arab countries and the Israeli government having authorized the use and assembly of nuclear weapons, the United States began an overt operation to airlift materiel to Israel. As Schlesinger explained, the initial U.S. policy to avoid direct involvement rested on the assumption that Israel would win quickly. But when it became clear that the Israelis faced more formidable military forces than anticipated, and could not meet their own resupply arrangements, the United States took up the burden. According to Henry Kissinger, with the president's authority, the directive was made to resupply Israel with the needed equipment and eliminate State Department delay. "It was alleged that the airlift was deliberately delayed as a maneuver to pressure Israel." Schlesinger rejected charges that the Defense Department delayed the resupply effort to avoid irritating the Arab states and that he had had a serious disagreement over this matter with Secretary of State Henry Kissinger. Eventually the combatants agreed to a cease-fire, but not before the Soviet Union threatened to intervene on the Arab side and the United States declared a higher level worldwide alert of its forces.