At the very root of the human experience lies the concept of "them" and "us."

"We" is our family, our village, our region, our nation and our religious fellows. "They" is the other family, the next village down the river, the people who lie over the mountain and the ones whose God and worship differ greatly from our own.

The history of "them" and "us" is one of great violence. The hope of the modern era has been that we will overcome the hatreds and become, if not one human culture, then a multiplicity of cultures that coexist without hate or fear at the root of those relationships. Yet preserving and achieving that dream is one of the world's most compelling challenges.

How strongly will the United States commit to stopping those who preach vitriol and inspire killings? Who can we count as our allies as we strive? Who, and what, is the enemy?

It has been a brutal time for those who believe the peoples of the Earth can someday coexist in peace. Boko Haram, a vicious anti-Western Islamic terrorist group, is killing civilians with abandon in Nigeria and Cameroon. The Islamic State group is massacreing Kurds, slaughtering Egyptian Christians, beheading Americans and killing Muslims who don't actively share their dream of a caliphate. In Copenhagen, a gunman attacked a free-speech forum where a cartoonist known for depictions of Mohammed that anger some Muslims was slated to appear. Hours later, the gunman opened fire at a synagogue.

Israeli Prime Minister Benjamin Netanyahu's recent exhortation that the Jews of Europe would be safer residing in Israel strikes a chord of Jewish suffering that stretches back centuries, to the pogroms and the Inquisition. It is frustrating and frightening that such an offer still resonates today. And if the Jews should go to Israel, where should the Palestinians go? What about the Christians of the Middle East? Is Netanyahu only propagating the same us-versus-them mentality?

The war on terror is against those who twist the teachings of Islam, not Islam itself, as President Barack Obama said in Washington last week at an international summit on countering violent extremism. Unfortunately, some policymakers and certain news outlets are too preoccupied with deciding how to label violent extremists, while meaningful strategies to stop radicalization at home and abroad get too little attention.

How much will the United States and other nations commit to stopping the mayhem? A recent poll showed that Americans' support for ground troops to fight the Islamic State has ticked up to 47 percent. But as with recent conflicts, those feelings can change when our daughters and sons begin to come home in body bags. And we've learned that short-term commitments to extinguish extremist violence abroad don't always have a lasting effect, and may incubate as much jihadism as they extinguish.

We know that some bombing, a few months of ground troops and a "Mission Accomplished" banner won't create lasting change.

 

The United States must lead and unite help from all other nations that claim to stand with us in pursuing a battle against violence and hatred and killing. But military battles must be fought mostly by those nations and peoples at greatest risk -- Muslim nations and others most threatened by the Islamic State. These nations must become fairer and freer, and must present a superior option to what the terrorists are selling. No nation can be allowed to sponsor terrorism and remain in good standing in the eyes of free nations. No religious leader can be tolerated if his or her aim is to kill.

The march toward a tolerant, peaceful, free and prosperous world comes at a cost, as it has before. But we must continue to fight toward that goal, even when evil persists in blocking our path.