U.S. Army Photo by Sgt. Michael Abney

Eight years have passed, but the war that began on Sept. 11, 2001, has yet to be won. More and more Americans disagree on how to wage that war. Some even disagree there was ever a war, and still others--a growing number it appears--believe that the war can never be won.

It is hard to win any war; it is impossible to win a war if we cannot agree who the enemy is, nor whether or how to fight him. The challenge of how to avoid another terrorist attack appears to demand an answer, yet we drift inexorably away from a definitive response. Too many now choose to redefine the question (what war on terror?), or deny there is any question at all.

First to the good news: There have been hard-fought successes since 9/11. The liberation of Afghanistan and Iraq--like the liberation of Europe in the last century--should be a lasting and epochal achievement. The replacement of a dictator in the one and a rabid theocracy in the other are not quite the nullities that opponents claim. These are not total victories either, but in each case, military and civilian leaders believe success is achievable.

And there are other achievements too. There is the long-sought turnaround by the Pakistani government that has resulted in the death of Beitullah Mehsud and other terrorist leaders. Intelligence cooperation and joint targeting have enabled Washington and Islamabad to turn the tables on a variety of Taliban-related groups, stem the tide into Afghanistan and push back (albeit in limited fashion) on destabilizing extremists operating inside Pakistan's tribal areas and elsewhere.

All in all, we have successfully kept the perpetrators of the attacks on 9/11--and their supporters--on the defensive and from our shores. Lest anyone forget, the 1990s were marked by a series of terrorist attacks on Americans both here and abroad--none of which we responded to in any significant way: 9/11 marked the culmination of a period of insecurity; not its start. Al-Qaida has fallen on hard times, thanks to better intelligence, better targeting, better understanding of its operations and more willingness on the part of the United States to pull the trigger.

Nevertheless, the enemy that attacked us eight years ago and the ideology that succored it have continued to adapt, and in some cases, flourish. Related Islamist movements are far from failing. From Yemen to Somalia, Nigeria to Egypt, across Southeast Asia, and, still, in Pakistan, Islamist terrorist groups continue to operate with impunity.

Moreover, no number of UCAVs, no number of troops, no number of Special Forces or intelligence operatives can rout their way through the alphabet from Algeria to Yemen. The war that began on 9/11 cannot be ended on the battlefield. For sustainable victory in the long term, it is the very notion that Allah, the Quran and Sharia are the only proper tools for governance--the only key to the resurgence of the Islamic world--that must be defeated. And the only way it can be defeated is on the battleground of ideas.

Islamist extremists flourished in the 1990s because they were the only answer to secular dictatorships that had led most of the Muslim world into the swamps of increased poverty, decay and corruption. They shrank back in the face of allied power in the aftermath of 9/11, but have steadily clawed their way back to popularity in recent years. The oxygen that sustains them is supplied by the people of what President Obama has labeled the "Muslim world," people who do not live in free societies, who are denied opportunity by dictators, who are still looking for answers to what ails them.

Al-Qaida could not have grown roots in Afghanistan without the Taliban, who in turn would not have risen absent the failure of successive earlier governments. The Muslim Brotherhood would not be growing without the stifling dictatorship of Egyptian President Hosni Mubarak. In each instance, such groups thrive on the absence of political choice. Poll after poll has shown that they cannot achieve majorities in a multiparty democracy; it is only when Islamists are the sole alternative to the status quo that they win.

Sadly, the new American administration has decided to put expanding liberty on the back burner. Democracy, the president explained in his repudiation of the freedom agenda in Cairo, is not the answer, and "no system of government can or should be imposed upon one nation by any other." And while history suggests that the president's statement is neither accurate as a matter of fact nor statecraft, it suggests a moral equivalence about governance that is contrary to America's founding principles. Practically, it leaves us stuck with the odious choice of either abandoning the battlefield of ideas to the jihadists or making that battlefield a real one in which lives of American servicemen are sacrificed for short-terms gains bereft of vision for a more secure future.

Danielle Pletka is vice president for foreign and defense policy studies at AEI.