After the attack on Pearl Harbor, Japanese-Americans were put in concentration camps. That there was no comparable overreaction after 9/11, and that we have been able to preserve a free and open society, owes much to the fact that for 10 years there has been no repetition of those terrible attacks.

Preventing further attacks required the U.S. to drop its law-enforcement approach to terrorism and recognize that we were at war. Consider the difference between Khalid Sheikh Mohammed—the mastermind of 9/11 who told us much of what we now know about al Qaeda—and his nephew Ramzi Yousef, the mastermind of the 1993 attack on the World Trade Center who can't be questioned (even most courteously) without his lawyer present and has told us nothing of significance. Or consider the difference between the ineffective retaliatory bombing of Afghanistan in 1998 and the 2001 response that brought down the Taliban regime.

"That we made mistakes in Afghanistan and Iraq does not prove that we overreacted." -- Paul Wolfowitz

We went to war with Germany in 1941 not because it had attacked Pearl Harbor but because it was dangerous. After 9/11, we had to do more to deal with state sponsors of terrorism than simply place them on a prohibited list, especially if they had connections to biological, chemical or nuclear weapons. Saddam Hussein—who was defying numerous United Nations resolutions and was the only head of a government to praise 9/11, warning that Americans should "suffer" so they will "find the right path"—presented such a danger.

That we made mistakes in Afghanistan and Iraq does not prove that we overreacted. (Costly mistakes were also made in World War II: sending poorly prepared troops to North Africa, failing to plan for the hedgerows beyond the beaches at Normandy, failing to anticipate the German counterattack in Belgium.) The real question is whether a significantly different response would have produced a better result.

Would massive strategic bombing of Afghanistan—the 1998 response on a larger scale—been enough to defeat al Qaeda? Would the failing sanctions against Iraq not have collapsed and left us today with a Saddam Hussein committed, as he told his FBI interrogator, "to reconstitute his entire WMD program"—chemical, biological and even nuclear? What about the Libyan WMDs that Moammar Gadhafi gave up after he saw Saddam's fate?

Unfortunately, after it turned out we had been wrong about the existence of WMD stockpiles in Iraq, some accused President Bush of having overreacted or, even worse, of having lied. Others charged that our overreaction "gave democracy a bad name." Nonsense. Tens of thousands of Arabs today are risking their lives in Syria and elsewhere, not for bin Laden's dream of a heavenly paradise but for freedom and democracy.

Paul Wolfowitz is a visiting scholar at AEI.