For critics of American foreign policy, it’s all but axiomatic that the designation of a violent act as “terrorism” says as much about the accuser as it does about the accused. The US government itself can’t decide on a single working definition of the term, but a standard one denotes unlawful politically-motivated violence designed to intimidate a government or civilian population. Put pressure on any part of this definition and it starts to buckle.

“Unlawful”? Why can’t terrorists — as per the word’s original meaning — be state actors? “Civilian population”? The category becomes meaningless if individuals can be retroactively subtracted from it for the crime of being struck by an American drone.

The arrest of Dzhokhar Tsarnaev last weekend has most obviously raised questions about what the state sees as constitutive of “political motivation.” As several commentators have pointed out, we have scant evidence that the Boston marathon bombing suspect’s motives were more “political” than those of mass-murderers like James Holmes or Adam Lanza — yet only the Muslim immigrant inspired Republican fantasies of eviscerating an “enemy combatant.”