Recently our country killed a U.S. citizen with a rocket attack from a predator drone. He was not tried or even arrested.
Why undermine the trust of the American people to avoid doing the tiny extra amount of work entailed by capturing and trying someone? How do I know that what I say won't get me murdered in my sleep now? How do you know that?
It does not seem like a lot to ask that the government at least bother to arrest people and put on a mock trial for them before killing them. The constitution demands that it do so and we certainly have the resources to make it happen.