The Cold War, the third major conflict of the twentieth century, is no exception to this rule. All three phases can be identified, and all three triggered intense debate.

There were, for example, those who questioned whether the Cold War was in fact necessary and whether the Soviet Union and Communism constituted a threat. Such “revisionists” were a distinct minority, which is a good thing, as there is no reason to believe that the Soviets and Communism were a benign force. As a result, the Cold War, a four-decade-long global struggle, became a reality.

There was also an ongoing debate about how best to wage the Cold War throughout its history. The two principal schools of thought were “roll back” and “containment.”  The former argued that nothing less than overthrowing communism – “regime-change” in today’s parlance – would do.

The latter approach held that efforts to roll back Communism in the short run were too risky, given the Soviet nuclear arsenal, and that the United States and the West should content themselves with limiting the spread of Soviet power and influence.

Containment prevailed, but this hardly settled the debate, as there were intense arguments both over where it should be applied (Vietnam, Central America, and the Middle East all come to mind) and how it should be carried out, i.e., the right mix of military force, covert action, diplomacy and arms control, and economic sanctions and assistance.

And now, exactly 20 years after the Berlin Wall came down, we are well into the third phase – the debate over why the Cold War ended when it did and how it did.

One school of thought maintains that the Cold War was won as a result of decades of sustained US and Western pressure on the Soviet Union and its allies. This pressure at various times took the form of US, British, and French nuclear programs; NATO’s willingness to counter Warsaw Pact deployments of both conventional military and tactical nuclear forces; the decision to defend South Korea against the North’s aggression; the arming of the mujahedeen in Afghanistan to bleed Soviet occupation forces; and the decision to build a costly missile-defense system aimed both at negating the Soviet Union’s principal military investment and bankrupting its government.

A second and very different school of thought emphasizes less what the West did and more what the Soviet Union was. In this narrative, the Cold War was not so much won by the US and the West as lost by the Soviets, the inevitable result of Soviet economic weakness and political decay.

Yet another perspective stresses that Western willingness to engage the Soviet Union as much as confront it played a major role in how history turned out. Détente helped to keep the competition from spilling over into conflict as it exposed the Communist world to Western ideas of freedom and capitalism along with their benefits. The Soviet and other top-heavy regimes increasingly found themselves losing the battle of ideas and, as a result, the support of their own citizens.

All of these factors played a part. Western willingness to deny the Soviets success was an essential component of strategy. But this alone would not have been enough; indeed, the Cold War could well have turned hot if Western strategy had consisted only of military competition and confrontation. It was important to moderate the competition in order to allow pressure for change to build up from within the Soviet bloc. And it was important to expose the societies under Soviet control to their shortcomings and to the advantages of outside ideas.

All of the above has implications for today’s challenges. To be sure, there is no global threat on the scale of the former Soviet Union, but there are dangerous challenges emanating from such countries as Iran and North Korea. What is required is a policy on the part of the global community that mixes military strength with a willingness to negotiate and interact, a policy of collective strength and collective flexibility.

It is important here to keep in mind that containment, the dominant doctrine of the Cold War era, sought to push back against Soviet and Communist expansion – not just to limit the reach of Soviet power, but to frustrate it – in order to create a context in which the inherent flaws of communism and authoritarian rule would come to the fore. Mikhail Gorbachev could only have done what he did amidst a crisis of confidence.

Today, the world needs to create similar crises of confidence in the minds of those ruling Iran and North Korea. The goal should be to limit what they can accomplish in the short term; to get them to change their policies in the medium term; and to set in motion forces that will bring about new and fundamentally different governments and societies in the long term. Such an approach served the world well during the Cold War; it could do the same now.

Richard N. Haass is President of the Council on Foreign Relations and author of War of Necessity, War of Choice: A Memoir of Two Iraq Wars.
© Project Syndicate 1995–2009