I would say it was very effective, but I would draw a lot of continuity between the policies of the Nixon/Ford, Carter, and Reagan administrations and dispute that there was really any end to détente. The Helsinki Accords remained firmly in place, and Reagan followed the terms of SALT II until 1986, and nonetheless he also negotiated and signed the INF Treaty and started the START negotiations which were wrapped up by his successor, President Bush. The proxy war in Afghanistan was actually initiated by Reagan's predecessor, President Carter, and Carter's National Security Adviser, Zbigniew Brzezinski, and Reagan continued that effort. Reagan also conducted some anti-communist operations in Central America, which I would criticize, but which stands out as his major departure from Kissinger's détente or Brzezinski's Afghan policy. Another important aspect of the policies initiated by Kissinger/Brzezinski and continued by later administrations, including Reagan's, was the opening with China which took advantage of the Sino-Soviet split. So, my conclusion would be that Kissinger's policies were effective, and that Reagan's policies, with the exception of Central American policy, were a continuation of Kissinger's (and Brzezinski's) concepts for winning the Cold War. But I would also emphasize that the most important factor in ending the Cold War was not even American strategy, it was the failure of Communism and the internal collapse of the Warsaw Pact and the Soviet Union.