ties with the U.S. had been strained during Jimmy Carter's presidency due to Pakistan's nuclear program and the execution of Zulfikar Ali Bhutto in April 1979, but Carter told National Security Adviser Zbigniew Brzezinski and Secretary of State Cyrus Vance as early as January 1979 that it was vital to "repair our relationships with Pakistan" in light of the unrest in Iran. According to former CIA official Robert Gates, "the Carter administration turned to CIA ... to counter Soviet and Cuban aggression in the Third World, particularly beginning in mid-1979." In March 1979, "CIA sent several covert action options relating to Afghanistan to the SCC [Special Coordination Committee]" of the United States National Security Council. At a 30 March meeting, U.S. Department of Defense representative Walter B. Slocombe "asked if there was value in keeping the Afghan insurgency going, 'sucking the Soviets into a Vietnamese quagmire?'" When asked to clarify this remark, Slocombe explained: "Well, the whole idea was that if the Soviets decided to strike at this tar baby [Afghanistan] we had every interest in making sure that they got stuck." But a 5 April memo from National Intelligence Officer Arnold Horelick warned: "Covert action would raise the costs to the Soviets and inflame Moslem opinion against them in many countries. The risk was that a substantial U.S. covert aid program could raise the stakes and induce the Soviets to intervene more directly and vigorously than otherwise intended." In May 1979, U.S. officials secretly began meeting with rebel leaders through Pakistani government contacts. A former Pakistani military official claimed that he personally introduced a CIA official to Gulbuddin Hekmatyar that month (Freedom of Information Act requests for records describing these meetings have been denied). Additional meetings were held on 6 April and 3 July, and on the same day as the second meeting, Carter signed two presidential findings permitting the CIA to spend $695,000 on non-military assistance (e.g., "cash, medical equipment, and radio transmitters") and on a propaganda campaign targeting the Soviet-backed leadership of the DRA, which (in the words of Steve Coll) "seemed at the time a small beginning." By December 1979, Amin's government had lost control of much of Afghanistan, prompting the Soviet Union to invade the country, execute Amin, and install Parcham leader Babrak Karmal as president. The full significance of the U.S. sending aid to the mujahideen prior to the invasion is debated among scholars.