By GLEN E. HOWARD

Mr. Howard is president of the Jamestown Foundation

EXCERPT FROM ARTICLE:  Equally important: In less than a year, the U.S. and other Western countries will dispatch nearly 3,000 athletes and 500,000 spectators to the 2014 Winter Olympics in the Russian Black Sea town of Sochi. Sochi is on the western fringes of the North Caucasus, with Russia’s beleaguered Muslim minorities close by. Ever since the horror at Munich in 1972, security at the Olympics has been a high-tension business, but Sochi could be the most dangerous Games in four decades.

In addition to having a predilection for high-profile acts of terror, Boston Marathon bomber Tamerlan Tsarnaev and al Qaeda chief Ayman al-Zawahiri have at least one other thing in common: Both spent months in the mountainous Russian republic of Dagestan, a thriving center of global jihadist activity.

Zawahiri visited Dagestan in the mid-1990s and was detained there for six months by Russian security services. Tsarnaev spent seven months in the region last year visiting his father, who had just returned there from the United States. Tsarnaev, who was born in Kyrgyzstan, traveled on a fake Russian passport because U.S. authorities, citing a 2009 domestic-violence complaint against him, had denied his application for citizenship.

Located in Russia’s volatile North Caucasus region—between the Caspian and Black seas, in the country’s southwest—Dagestan is home to assorted militant groups that combine jihadist ideology with their aim of independence from Russia. The same is true in the neighboring region of Chechnya.

Militants launch violent attacks in Dagestan’s capital, Makhachkala, on a weekly if not daily basis, and while visiting there Tsarnaev would have had little trouble reaching out to local insurgents for training. One of the YouTube videos posted by his brother and accused co-conspirator, Dzhokhar, cited the deceased Dagestani militant Rappani Khalilov, who was killed by Russian security services in 2007. An associate of the noted Chechen warlord Shamil Basayev, Khalilov was skilled in guerrilla tactics and urban insurgency, glimpses of which were seen in the Tsarnaev brothers’ shootout last week with Boston police.

While one of the leading Dagestani militant groups has issued a statement rejecting any ties to the Boston bombings, there are many suggestions that the brothers had Dagestan on their minds. According to their uncle (with whom I have spoken), the leading force behind Tamerlan’s increasing religiosity in recent years was the boys’ mother, Zubeidat, an ethnic Avar from Dagestan. Their father, a Chechen, is more secular. Postings to Twitter show the boys rooting for the Dagestani soccer club called Anzhi, rather than the Chechen club, Terek.

Yet the Chechen jihad couldn’t have been far from the men’s thinking. One of the books listed on Tamerlan’s Amazon.com AMZN -2.20%wish list was “The Lone Wolf and the Bear: Three Centuries of Chechen Defiance of Russian Rule.” Chechnya’s reputation for skill in fighting Russia (mentioned frequently, for example, in the writings of al Qaeda figure Abu Musab al-Suri) has elevated Chechens to high social status in Muslim communities around the world.

The special status bestowed on Chechens makes Chechen youth especially appealing to Islamist clerics who seek to radicalize and deploy them as foot soldiers in the global jihad against the U.S. and its allies. Tamerlan Tsarnaev might have appeared especially appealing for such a role, given his prowess as an amateur boxer in and around Boston.

While it is too early to tell, I suspect that Tamerlan was radicalized in the U.S. but used his months in Dagestan to receive the military training and bomb-making skills needed for the Boston attack. If true, then this occurred right under the noses of the Russian security services that work very hard (and brutally) to keep down insurgents in the North Caucasus. Russian authorities tipped off the FBI about Tamerlan’s radical leanings in 2011, but still they didn’t detain or arrest him during his extended 2012 visit to Dagestan.

Since the mid-1990s, the U.S. has largely ignored Chechnya’s separatist wars against Russia and Russia’s suppression of its Muslim minorities. The conflict has spread from Chechnya to other parts of the North Caucasus, effectively Balkanizing southern Russia. With the Boston bombing, the U.S. would do well to take a more active role in addressing this conflict-ridden region.

The increasing Balkanization of Russia’s southern frontier will likely push more refugees like the Tsarnaevs to seek asylum in the U.S. and Europe. While my research suggests that fewer than 200 Chechens currently reside in the U.S., more than 200,000 Chechen refugees have fled to Western Europe since 1999. Many have obtained European passports and travel back and forth to their homelands all across the North Caucasus. The offspring of these refugees—like Tamerlan and Dzhokhar Tsarnaev—often resent that more than 200,000 Chechens have died in wars with Russia since 1994, and radical clerics can prey on this resentment as they seek recruits for international terrorism.

It is important that the U.S. continue counterterrorism cooperation with Moscow (even as the Kremlin tries to dismiss all of its opponents as terrorists or other enemies of the state). But Washington should balance its cooperation with Moscow by reaching out to staunch American allies in the region—such as Georgia and Azerbaijan, which border the North Caucasus—to glean insights and exchange information about threats.

Equally important: In less than a year, the U.S. and other Western countries will dispatch nearly 3,000 athletes and 500,000 spectators to the 2014 Winter Olympics in the Russian Black Sea town of Sochi. Sochi is on the western fringes of the North Caucasus, with Russia’s beleaguered Muslim minorities close by. Ever since the horror at Munich in 1972, security at the Olympics has been a high-tension business, but Sochi could be the most dangerous Games in four decades.

Mr. Howard is president of the Jamestown Foundation.