Many people have good ideas, but few live to see those ideas define an era and even win a war. George Kennan did, even though he eventually backed away from the ramifications of his idea.

In 1946, as the United States was trying to decide how to deal with the post-World War II world, Kennan weighed in with the famous "Long Telegram" from Moscow. The Soviet Union is "impervious to the logic of reason," Kennan warned his superiors at the State Department, but "it is highly sensitive to the logic of force."

Thus began the policy of containment -- a word Kennan first used a year later when he reworked the Long Telegram for an article in Foreign Affairs.

Kennan was writing at an especially difficult time. The Soviets had played a key role in defeating Germany, and many Americans hoped to work with dictator Joseph Stalin to shape the post-war world. But Kennan encouraged us to see the Soviet Union for what it was: A power-hungry nation that would attempt to bully us, but would back down as long as it realized we were willing to fight.

Washington should threaten the Soviets "with unalterable counterforce at every point where they show signs of encroaching upon the interest of a peaceful and stable world," he wrote. And if we kept that pressure up, Kennan predicted that we would "promote tendencies which must eventually find their outlet in either the break-up or the gradual mellowing of Soviet power."

Of course, Kennan didn't agree with every facet of our containment policy as it developed across the years.

He didn't want us to confront the Soviets head on, military to military. In fact, he actually opposed the use of force. He opposed the formation of NATO, the defense of Korea in the 1950s and American military intervention in Vietnam in the 1960s. The cautious diplomat didn't want to see the Cold War turn hot.

But by fighting non-nuclear proxy wars, the U.S. showed the Soviets we would be willing to use force to defend freedom, anywhere in the world. If they pushed with arms, we'd push back. That was critical to our eventual victory in the Cold War. Because presidents from Truman through Reagan were willing to use military power, the Soviets were unable to expand in Greece, South Korea and other areas.

Kennan was far happier with our economic policy, and helped craft the Marshall Plan, which provided billions of dollars in aid to western Europe. The Soviets faced a choice: Accept our money and, in doing so, admit that our capitalist system was more effective than their communist system, or refuse our money and isolate themselves from the West.

They chose isolation, and from that point on -- by their own choice -- were effectively "contained" economically. The great post-war boom that built the modern world and rebuilt our former enemies Germany and Japan passed right by the Soviet Union and its satellites.

Meanwhile, we also attempted to defeat communism through other means. The covert-operations directorate of the CIA was also Kennan's idea. He wanted to use it to conduct "political warfare" against Moscow, which it did for many years, most successfully in Afghanistan during the 1980s.

Eventually, the U.S. was able to move beyond mere containment and confront Moscow more directly. When President Reagan refused to give up the Strategic Defense Initiative, Soviet Premier Mikhail Gorbachev knew it was time to yield. The Iron Curtain came down, just as Kennan had predicted it would.

Kennan died recently at the age of 101. It's fitting that he outlived the Soviet Union. After all, even though he didn't always agree with the methods Americans used to win the Cold War, he essentially authored the policy that ultimately defeated communism.

Ed Feulner is president of the Heritage Foundation.