If the tool runs contrary to due process and checks and balances then it is a toxic tool.
The way to put a useful tool in right hands of a governing body is to ensure that its use is limited so that wrongful uses and the degree of malfeasance is [regardless whose hands this power sits within], is limited or subject to appropriate overcite.
If the means justify the ends a post killing judicial review (i.e. a wrongful death action by the father/Civil suit against President Obama) should at least be an option if for whatever reason a prekilling review is unacceptable. One of the equitable remedies sought could be an injunction against the President absent judicial review or a specific law [suviving constituional muster] granting the President the power for this type of killing by a majority of the federal Congress.