Last week, I wrote a column that made three simple points. First, many of Islam's most vociferous defenders -- members of our so-called cultural elite -- are in fact quite ignorant about the religion. Second, it is difficult for any non-Muslim to define "true Islam," especially when Muslims themselves have debated (and fought over) their own religion for more than 1,000 years. Finally, I noted that -- regardless of the definition of "true Islam" -- the religion is currently generating thousands of suicide bombers, hundreds of thousands of jihadists, and millions more jihadist sympathizers and supporters.

I've made this argument in a variety of contexts: in print, in speeches, and in conversations with thoughtful people on the left and right. Even if they accept my premises (and they often do not -- somehow believing that people like Michael Bloomberg and President Obama have real insight into the heart of the Muslim world), their next question is quite logical and sensible: What do you propose we do? If there is "something rotten at work within Islam," how do we fight it without triggering a general war against the Muslim world?

My answer is disappointingly unoriginal. We need to keep doing what we're doing. But we cannot have false hope for short-cuts to victory, and we must have the grim resolve necessary to fight a long war.

Simply put, there is no way to appease radical Islam. Or, if you prefer that I not use a loaded world like appease, radical Islam makes demands that cannot be met. Can we permit Israel to be destroyed? Can we return Spain to an Islamic dictator? Can we allow the creation of an Islamic Caliphate, utterly opposed to the existence of western civilization? These are the demands of radical Islam.

If radical Islam cannot be appeased, it must be defeated. How does one defeat an idea? First, it is vital to understand that radical Islam draws strength from success, not failure. When Osama bin Laden declared that people back the "strong horse," he was declaring a key part of radical Islam's message: that they alone offer the strength to restore the Islamic world to its past glory. Their martyrs are not martyrs in the Christian sense -- those whose suffering models that of Christ; their martyrs are more like Kamikazes, suicide bombers who kill to achieve a military and political objective.

American military weakness encourages radical Islam (bin Laden references, for example, America's retreat from Somalia following the Battle of Mogadishu), and its defeats profoundly discourage its own followers. I served in Diyala Province, Iraq, at the height of the surge, and I saw al Qaeda's support literally melt away as we reclaimed villages and defeated insurgent cells. As their prospects for success -- for creating the Islamic Caliphate of Iraq -- dimmed, so did their morale. By Fall 2008, the unthinkable occurred: al Qaeda insurgents began to turn themselves in, exhausted, demoralized, and drained of all hope.

Defeating Islamic radicals does not require a "war against Islam," but it does require long-term commitment, and a demonstration to the rest of the Islamic world that al Qaeda's primary weapon -- its ability to kill -- cannot weaken our resolve. We may never destroy radical Islam entirely, but we can contain the virus, weaken it, and relegate it to a tiny, relentlessly hunted minority.

As radical Islam faces defeat on the battlefield, it is discredited in the wider Islamic world. No movement that fails to provide promised victories can maintain credibility over the long term, and this is especially true for jihadists whose entire reason for being is waging victorious holy war. Military targets are much more difficult than civilian, and western civilian targets more difficult than Arab civilian, so we've seen radical Muslims aim the vast majority of their suicide bombs at fellow Muslims. It is one thing for the "Arab street" to admire a bomb in a U.S. Embassy or an Israeli café. It is another thing entirely to live in a city where your own market, your own hospital, and your own restaurants become scenes of frightful carnage.