Charles King downplays its significance:
[T]here is no direct information linking the North Caucasus to the attack in Boston; armed groups in the region, including the Dagestani branch of the so-called Caucasus Emirate — the jihadist network in the North Caucasus headed by Chechen warlord Doku Umarov — issued a formal statement denying any connection to the Tsarnaev brothers. The jihadists claimed instead that the brothers were pawns in an elaborate attempt by Russian security services to turn American opinion against the North Caucasus underground and against Muslims more generally. That might be far-fetched, but it would hardly be the line of argument the Emirate would pursue if it were suddenly using American operatives to expand attacks outside of Russia. The logical thing would have been for the Emirate to claim responsibility.
Instead, he argues that the bombing might have more implications for the ongoing violence in Syria:
There are somewhere “between 600 and 6,000” Chechens from the North Caucasus fighting in Syria, said Kotliar in a recent interview with Russian media, “and from what happened in Boston, perhaps Americans will finally draw the lesson that there are no good terrorists and bad terrorists, no ‘ours’ and ‘yours.’” Keep arming the Syrian rebels, the argument goes, and sooner or later you will have to face the consequences of a Syria overtaken by Islamist radicals.
Larison isn’t buying it:
Considering how strongly opposed Russia already was to Western intervention and to any Western support for the Syrian opposition, I don’t know that their opposition can be “hardened” much more than it is. American public opinion was already heavily against greater U.S. involvement in Syria before the bombings, and the Syria policy debate among politicians and pundits will likely remain more or less unchanged.