Having been an expert witness in several Guantanamo Habeas Corpus cases that stretched on interminably and having served the same function in Article Three criminal cases involving national security I would heartily recommend that Tsarnaev be tried in federal civilian court.
In my experience the Department of Justice and the FBI are more than qualified and quite willing to prosecute such cases. There is an abundance of evidence in this case and any links to a larger group than the two brothers will soon be uncovered.
Any idea that a Military Commission under the present law would deal with the culprit(s) more severely than a civilian court is misguided. Having been "burned" by the experience of the mistreatment of prisoners in the immediate post 9/11 world the military can be expected to be very wary of any such idea. Under pressure from Cheney and Rumsfeld, carefully chosen commanders did things then that were outside the traditions and regulations of the US armed forces. The armed forces have payed a price for that in reputation and corruption of their institutions and will not repeat the error. It would be much better to let the civlian courts deal with this matter.
BTW, the claim that the US government has been opposed to Soviet/Russian government actions against the Chechens in Chechniya is nonsense. At the level of working government there has been a constant cooperation on the basis of anti-terrorism since the emergence of salafi wahhabi elements among the Chechen guerrillas in; Chechniya, the Balkans, Iraq and Afghanistan. FSB (formerly KGB) witnesses who have worked on the Chechen "problem" for decades are routinely called as prosecution witnesses in US federal courts in cases whree their "expertise" is useful. The Chechens know this.
We should remember that the Chechens and other Northern Caucasian minority "nations" have resisted Russification and Westernization for centuries. Until recently they were led in this resistance by their own Sufi murids. these Sufis were in no way either salafi or wahhabi. pl