The defining challenges of the twentieth century ended with the fall of the Berlin Wall. Full recognition of the first great challenge of the twenty-first century came with the attacks of September 11, 2001, even though Islamist terrorists had begun their assault on world order decades before. Confronted with an act of war on American soil, our old assumptions about conflict between nation-states fell away. Civilization itself, and the international system, had come under attack by a ruthless and radical Islamist enemy.

[W]e are up against a truly malignant force in radical Islamism and in the states breeding, sheltering, or financing its terrorist armory. This new enemy has already attacked us on our own soil—a feat neither Nazi Germany nor Soviet Russia ever managed to pull off—and openly announces his intention to hit us again, only this time with weapons of infinitely greater and deadlier power than those used on 9/11. His objective is not merely to murder as many of us as possible and to conquer our land. Like the Nazis and Communists before him, he is dedicated to the destruction of everything good for which America stands. It is this, then, that (to paraphrase George W. Bush and a long string of his predecessors, Republican and Democratic alike) we in our turn, no less than the “greatest generation” of the 1940’s and its spiritual progeny of the 1950’s and after, have a responsibility to uphold and are privileged to defend.

Achieving a realistic peace means balancing realism and idealism in our foreign policy. America is a nation that loves peace and hates war. At the core of all Americans is the belief that all human beings have certain inalienable rights that proceed from God but must be protected by the state. Americans believe that to the extent that nations recognize these rights within their own laws and customs, peace with them is achievable. To the extent that they do not, violence and disorder are much more likely. Preserving and extending American ideals must remain the goal of all U.S. policy, foreign and domestic. But unless we pursue our idealistic goals through realistic means, peace will not be achieved.

Idealism should define our ultimate goals; realism must help us recognize the road we must travel to achieve them. The world is a dangerous place. We cannot afford to indulge any illusions about the enemies we face. The Terrorists' War on Us was encouraged by unrealistic and inconsistent actions taken in response to terrorist attacks in the past. A realistic peace can only be achieved through strength.

We look upon authority too often and focus over and over again, for 30 or 40 or 50 years, as if there is something wrong with authority. We see only the oppressive side of authority. Maybe it comes out of our history and our background. What we don't see is that freedom is not a concept in which people can do anything they want, be anything they can be. Freedom is about authority. Freedom is about the willingness of every single human being to cede to lawful authority a great deal of discretion about what you do.”

For somebody who declares democracy to be his goal, he [Podhoretz] is remarkably blasé about the fact that 80 percent of Iraqis want U.S. troops to leave their country, according to the latest polls. "I don't much care," he says, batting the question away.

The first step toward a realistic peace is to be realistic about our enemies. They follow a violent ideology: radical Islamic fascism, which uses the mask of religion to further totalitarian goals and aims to destroy the existing international system. These enemies wear no uniform. They have no traditional military assets. They rule no states but can hide and operate in virtually any of them and are supported by some.

Above all, we must understand that our enemies are emboldened by signs of weakness. Radical Islamic terrorists attacked the World Trade Center in 1993, the Khobar Towers facility in Saudi Arabia in 1996, our embassies in Kenya and Tanzania in 1998, and the U.S.S. Cole in 2000. In some instances, we responded inadequately. In others, we failed to respond at all. Our retreat from Lebanon in 1983 and from Somalia in 1993 convinced them that our will was weak.

The record speaks dismally for itself. From 1970 to 1975, several American diplomats were murdered in Sudan and Lebanon ... in 1979, with Carter now in the White House, Iranian students ... broke into the American embassy in Tehran and seized 52 Americans as hostages... In April 1983, Hizbullah—an Islamic terrorist organization nourished by Iran and Syria—sent a suicide bomber to explode his truck in front of the American embassy...Six months later, in October 1983, another Hizbullah suicide bomber blew up an American barracks in the Beirut airport...Having cut and run in Lebanon in October, Reagan again remained passive in December, when the American embassy in Kuwait was bombed...In September 1984...In December 1984... In October 1985...In December 1985.. December 1988 ...January 1989, Reagan was succeeded by the elder George Bush, who, in handling the fallout from the destruction of Pan Am 103, was content to adopt the approach to terrorism taken by all his predecessors...In January 1993, Bill Clinton became President...several spectacular terrorist operations occurred on Clinton’s watch of which the U.S. was most emphatically the target...

America must remember one of the lessons of the Vietnam War. Then, as now, we fought a war with the wrong strategy for several years. And then, as now, we corrected course and began to show real progress. Many historians today believe that by about 1972 we and our South Vietnamese partners had succeeded in defeating the Vietcong insurgency and in setting South Vietnam on a path to political self-sufficiency. But America then withdrew its support, allowing the communist North to conquer the South. The consequences were dire, and not only in Vietnam: numerous deaths in places such as the killing fields of Cambodia, a newly energized and expansionist Soviet Union, and a weaker America.

A primary goal for our diplomacy -- whether directed toward great powers, developing states, or international institutions -- must be to strengthen the international system, which most of the world has a direct interest in seeing function well. After all, the system helps keep the peace and provide prosperity. Some theorists say that it is outmoded and display either too much faith in globalization or assume that the age of the sovereign state is coming to a close. These views are naive. There is no realistic alternative to the sovereign state system. Transnational terrorists and other rogue actors have difficulty operating where the state system is strong, and they flourish where it is weak. This is the reason they try to exploit its weaknesses.

With the victorious conclusion of World War III in 1989-90, the old international order became obsolete, and new arrangements tailored to a new era would have to be forged. But more than a decade elapsed before 9/11 finally made the contours of the “post-cold-war era” clear enough for these new arrangements to begin being developed.

Looked at from this angle, the Bush Doctrine revealed itself as an extremely bold effort to break out of the institutional framework and the strategy constructed to fight the last war. But it was more: it also drew up a blueprint for a new structure and a new strategy to fight a different breed of enemy in a war that was just starting and that showed signs of stretching out into the future as far as the eye could see. Facing the realities of what now confronted us, Bush had come to the conclusion that few if any of the old instrumentalities were capable of defeating this new breed of enemy, and that the strategies of the past were equally helpless before this enemy’s way of waging war. To move into the future meant to substitute preemption for deterrence, and to rely on American military might rather than the “soft power” represented by the UN and the other relics of World War III.

A hybrid military-civilian organization -- a Stabilization and Reconstruction Corps staffed by specially trained military and civilian reservists -- must be developed. The agency would undertake tasks such as building roads, sewers, and schools; advising on legal reform; and restoring local currencies.

The 9/11 generation has learned from the history of the twentieth century that America must not turn a blind eye to gathering storms. We must base our trust on the actions, rather than the words, of others. And we must be on guard against overpromising and underdelivering. Above all, we have learned that evil must be confronted -- not appeased -- because only principled strength can lead to a realistic peace.