Early reports suggest that the two suspected Boston Marathon bombers, Tamerlan and Dzhokhar Tsarnaev, are ethnically Chechen. Media reports suggest their family lived in Chechnya in the 1990s and later moved to neighboring Dagestan and then Kyrgyzstan. The Tsarnaevs moved to the United States about a decade ago, and the younger brother, Dzhokhar, became an American citizen last year. The connection between Chechen expatriates and the former Soviet Union might prove critical to understanding why these two men allegedly turned to terrorism. Russia and Chechnya do not get along, to put it lightly. Chechnya is a tiny, autonomous republic in the southwest of Russia -- part of the Caucasus region between Europe and Asia between the Black and Caspian Seas. In 1944, Josef Stalin deported the entire population of the North Caucasus -- about 600,000 people in the republics of Ingushetia, Chechnya, and North Ossetia -- across the Caspian Sea to the Soviet republics of Central Asia on the suspicion they were collaborating with Nazi Germany. The mass deportation was catastrophic: Crowded, poorly ventilated trains dumped people in the middle of the steppe between Kazakhstan and Kyrgyzstan, stranding them in the vast wastelands with no supplies. Although Nikita Khrushchev eventually returned the displaced Chechens to the Caucasus in 1957, the scars of that dislocation never went away. In many ways, the Caucasian displacement led to the militancy and separatism that still haunt the region. After the fall of the U.S.S.R., some Soviet republics gained their independence. The "stans" of Central Asia -- Kazakhstan, Kyrgyzstan, Uzbekistan, Tajikistan, and Turkmenistan -- all became independent countries. So, too, did the countries of the South Caucasus -- Georgia, Armenia, and Azerbaijan. The North Caucasus, however, never gained independence from Moscow, though many wanted it. In the years after independence, the South Caucasus was ravaged by brutal ethnic wars in Georgia and between Armenia and Azerbaijan. By 1994, Chechnya had declared its own independence, and the Russian military surged into the country. The first Chechen war killed thousands of people, mostly civilians, and thousands more fled the republic looking for refuge. A lot of them settled in Central Asia because a sizable Chechen population had remained there since Stalin's forced relocation, particularly in Kazakhstan. But, over the subsequent two decades, they had trouble integrating and settling down. Refugees living in the former capital of Almaty reported being harassed by the police after the 9/11 attacks on the assumption they were terrorists. Chechens who settled in the northern part of the country faced arbitrary arrest and deportation back to Russia. In 2007, Refugees International wrote a scathing assessment of Kazakhstan's treatment of Chechen refugees, noting that the Kazakhstan government prioritized its relations with Russia over treating refugees fairly. There are conflicting reports over whether the Tsarnaev brothers lived for a brief time in Kazakhstan or in Kyrgyzstan. Fewer Chechens fled to Kyrgyzstan than to Kazakhstan, but those that did have faced similar difficulties settling in and feeling safe. In the second Chechen war, the Kyrgyz government was reluctant to recognize its refugee Chechen population for fear of antagonizing Russia, which under Vladimir Putin had brutalized the country and killed a large number of Chechen civilians.* During that war -- which first broke out in 1999, when Chechen militants invaded Dagestan and the Russian army was mobilized after a series of terrorist bombings killed almost 300 people -- Kyrgyz media portrayed Chechens as "cut-throats and monsters who kidnap people and trade them as slaves." Correction: A previous version of this sentence incorrectly referred to the "first Chechen war." As a result, many Chechens who fled to Central Asia did not find refuge, just harassment and continued uncertainty. It should not be surprising that thousands moved on, as apparently the Tsarnaev family did 10 years ago. The United States has been a country of refuge for people fleeing conflict in the former Soviet Union -- and not just in Chechnya. After the 2005 massacre in Andijon, Uzbekistan, for example, many Uzbeks who fled the government crackdown were able to settle in the United States. The United States has granted asylum to some Chechens who've fled the wars there, though we don't yet know if the Tsarnaev family was among them. We'll have to see if any of this sad history is relevant to this week's bombing in Boston. Chechens have had a raw deal, chased from country to country and rarely integrating well. The community where the two brothers were apprehended, Watertown, has a large Caucasus population, though it's unclear how many are Chechen. There are also enclaves of Chechens in California, and a few live in Washington, DC. But it is difficult for such small numbers -- perhaps only a few hundred in the whole country -- to form supportive expatriate communities. We have one hint that the Tsarnaev brothers weren't assimilating well. In a photo essay featuring Tamerlan, who died this morning in a shootout with the Boston police, he told the photographer, "I don't have a single American friend, I don't understand them." And in his profile on VK, a Russian-language social-networking site, Dzhokhar posted some YouTube videos that are supportive of Islamist extremism. There's little we can conclude right now about the motivations of these young men, but any personal alienation would have played out in front of a historical backdrop.