If it was conducted by international belligerents the Boston Marathon attack was clearly a violation of of both the Geneva Convention and international law. If it was carried out by a U.S.-based group or individual then U.S. law should be sufficient to put those responsible away for the rest of their lives. But none of that changes the fact that drones are still too inaccurate to justify using them the way the U.S. has been.
"It turns out that the Obama administration has not been honest about who the CIA has been targeting with drones in Pakistan."
Drone strikes in Yemen, Pakistan, Somalia and elsewhere are probably straight up illegal (under international law) to begin with, given that the U.S. isn't a declared belligerent in those conflicts. But the awful targeting makes it worse. Indiscriminate attacks are war crimes under the Geneva Convention (
Additional Protocol, Article 51), no matter if they're launched by the U.S. government or some jihadi terror group. America was supposed to be better than its enemies, but that standard was lost under President Bush and has gotten worse under President Obama. There's no moral high ground here - both sides should have their turn in front of the ICC to answer for their crimes.