. . . where one of the Boston Marathon suspects is dead and the other is on murderous rampage: It is very important that the remaining suspect be taken alive.
The New York Times has identified the two suspects as Chechen brothers, Dzhokhar A. Tsarnaev, 19, and Tamerlan Tsarnaev, 26---the latter of whom is apparently dead. The most important thing, of course, is to apprehend and stop the remaining suspect before anyone else is killed or hurt. That may require the use of lethal force, and the state and federal law enforcement officers who are dealing with this situation will use their best judgment as to how to protect the public---and themselves.
But it is critically important to understand what, if any, connection these suspects have both to overseas terrorist groups and to domestic folks not yet tied to the bombing, and that project will be far easier if the surviving Mr. Tsarnaev is not killed. The question is important both for obvious reasons---if some group is attacking the United States, we need to understand with maximum precision who that is and who is involved---and for less obvious legal reasons: Is this a home-grown terrorist problem that's purely a matter of criminal law? Is this a feature of the US's existing armed conflict with Al Qaeda and its associated forces? Or is this some new overseas terrorist threat---an extra-AUMF threat---against the United States playing out in the streets of Cambridge and Watertown? Or is this an example of a blurry line between categories? The chance to interrogate a Mr. Tsarnaev who can still talk is the quickest and easiest way to answer these questions.