The general consensus among historians is that Kissinger was incredibly influential in the crafting of US foreign policy, but this doesn't necessarily mean that he held a great deal of influence in terms of shaping international events.

As numerous historians have demonstrated, Kissinger effectively ensured that he was the sole purveyor of American foreign policy, with the exception of presidents Nixon and Ford. While he was National Security Advisor, he essentially made the department of state irrelevant by taking over many of the tasks, like communicating with foreign officials and heading foreign policy task groups, typically reserved to the secretary of state. By Nixon's second term, he was serving concurrently as National Security Advisor and Secretary of State, and had pushed out most other foreign policy advisors from the policymaking process.

What's less clear is whether Kissinger's foreign policy was able to have any significant impact on what was an incredibly complex international order. While Kissinger was in office, the world was undergoing significant upheaval. There were various international crises originating in the Third World, and there was also domestic unrest in every region of the world. This didn't sit well with Kissinger. The most important aspect of Kissinger's foreign policy outlook was his overriding concern of maintaining international stability, particularly by maintaining the Cold War's bipolar global order. Wars in Vietnam and the Middle East and domestic protests in the U.S. and Europe all threatened to upend the bipolar order. Kissinger believed that wars in the Third World might drag the two superpowers into military conflict or nuclear war, and domestic unrest in Western Europe could open that continent up to greater Soviet influence. Simultaneously, domestic unrest in the U.S., particularly protests against the Vietnam War, had the potential of leading the U.S. away from the global interventionism necessary to maintain its superpower status.

It's important to stress that Kissinger wanted the Soviet Union to remain a superpower, albeit one that was a little less super than the United States. He believed that it was necessary for the two superpowers to be strong enough to control their international allies because doing so would promote international stability. Simultaneously, Kissinger didn't want the Soviet Union to have a disproportionate level of global influence relative to the United States. He wanted a strong, but not a stronger, Soviet Union. With that in mind, many of Kissinger's most significant policies, like detente, can be seen as attempts to accomplish two things. First, to correct the instability that had plagued the international system since the mid-1960s. Second, to establish a bilateral diplomatic framework--detente--between the U.S. and Soviet Union that would mitigate Soviet attempts to gain a disproportionate level of global influence.

So, did Kissinger's policies achieve either of these objectives? The international order certainly became much more stable in the Kissinger years and remained so until the final years of the Carter presidency. In terms of mitigating the Soviet Union's global influence, however, Kissinger's policies failed. During the 1970s and 1980s, the USSR made large gains in the Third World, particularly in Africa, and those gains did much to reignite the "second Cold War" that began during Reagan's second term.

Reading Recommendations

There are four excellent biographies of Kissinger:

• Jeremi Suri, Henry Kissinger and the American Century (This book provides a more favorable view of Kissinger than most other biographers).

• Jussi Hahnimaki, The Flawed Architect: Henry Kissinger and American Foreign Policy

• Mario del Pero, The Eccentric Realist: Henry Kissinger and the Shaping of American Foreign Policy

• Robert Dallek, Nixon and Kissinger: Partners in Power

The following are excellent studies of U.S. foreign policy during the Nixon-Ford administrations:

• Daniel Sargent, A Superpower Transformed: The Remaking of American Foreign Relations in the 1970s

• Jeremi Suri, Power and Protest: Global Revolution and the Rise of Detente

• Barbara Zanchetta, The Transformation of American International Power in the 1970s

• Paul Thomas Chamberlin, The Global Offensive: The United States, the Palestine Liberation Organization, and the Making of the Post-Cold War World

• Gary Bass, The Blood Telegram: Nixon, Kissinger, and a Forgotten Genocide

Piggyback question: How seriously should we treat his alleged war crimes?

There's some discussion of Kissinger and his involvement in international affairs as a member of Nixon's administration in Conrad Black's Nixon biography, though it doesn't give a comprehensive view of his lifetime. His remarks are more informed by a personal relationship with Henry Kissinger, but he implies (and I believe states) that Kissinger has a tendency to exaggerate his importance.

Then again, though, the credibility of Conrad Black as a source can be brought into question, considering his unethical business practices which might be taken as a mark against his intellectual integrity. Wish I could offer more reading suggestions, but my knowledge is very skimpy.