Now, Americans can be targeted for extrajudicial assassination without even the slightest HINT of "due process", and courts are not "...equipped to make decisions about who qualifies as an enemy."?!?
Counsel Johnson, the US has dealt with a lot of "bad guys" in its history, but up until now, the notion deciding who is an enemy of the United States has been left largely to American jurisprudence, guided by the premise that any accused is considered "innocent until proven guilty." We have a method for making such a determination, and it is called the American legal process, which used to be the envy of people from around the world.
It appears that the blatant anti-Constitutional, anti-Bill of Rights stance you and your colleague would prefer to take is tantamount to the imposition of Code Napoleon law upon the citizens of this country, in which the accused is considered guilty until proven innocent, then offered absolutely zero due process whatsoever to prevent their killing by the Federal Government.
I respectfully suggest that you re-examine your premise for making these remarks, and please remember that we have a system of laws in place to prevent just such an actions as extra-judicial assassinations from being ordered by the executive branch of the US Federal government.