Victor Davis Hanson

British Prime Minister Neville Chamberlain was ecstatic after the Munich Conference of 1938. He bragged that he had coaxed Adolf Hitler into stopping further aggression after the Nazis gobbled up much of Czechoslovakia.

Arriving home, Chamberlain proudly displayed Hitler's signature on the Munich Agreement, exclaiming to adoring crowds, "I believe it is peace for our time. ... And now I recommend you to go home and sleep quietly in your beds."

But after listening to Chamberlain's nice nonsense, Hitler remarked to his generals about a week later, "Our enemies are little worms, I saw them at Munich." War followed in about a year.

Sometimes deterrence against aggression is lost with just a few unfortunate words or a relatively minor gesture.

Secretary of State Dean Acheson gave a comprehensive address to the National Press Club in early 1950. Either intentionally or by accident, he mentioned that South Korea was beyond the American defense perimeter. Communist North Korea, and later China, agreed. War broke out six months later.

Well before the Soviets invaded Afghanistan in 1979, and sent aid to communist rebels in Central America, President Jimmy Carter announced that America had lost its "inordinate fear of communism."

In 1981, Britain, as a goodwill gesture in the growing Falkland Islands dispute, promised to withdraw a tiny warship from the islands. But to the Argentine dictatorship, that reset-button diplomacy was seen as appeasement. It convinced them that the United Kingdom was no longer the nation of Admiral Nelson, the Duke of Wellington and Winston Churchill. So Argentina invaded the Falklands.

Why, after a horrendous war with Iran, would Saddam Hussein have risked another one with Kuwait? Perhaps because he believed that the United States would not stop him. That was a logical inference when American ambassador April Glaspie told him, "We have no opinion on your Arab-Arab conflicts, such as your dispute with Kuwait ... the Kuwait issue is not associated with America."

Saddam invaded a little over a week later.

These examples could be expanded and serve as warnings. In the last 18 months, the Obama administration has made a number of seemingly insignificant remarks and gestures -- many well-intended and reasoned -- that might be interpreted as a new U.S. indifference to aggression.

Consider the number of apologies Obama has issued to various states that suggest we, not others, are the problem.

To Turkey, Obama said we had often been at fault, and added remorse for slavery and our treatment of Native Americans.

To Russia, he emphasized a need for an American diplomatic reset button.

Victor Davis Hanson

Victor Davis Hanson is a classicist and historian at the Hoover Institution, Stanford University, and a recipient of the 2007 National Humanities Medal.