This problem is compounded by the possible presence of multiple chemicals which together have an additive effect that greatly increases the lethal action of any single chemical.

CNN: Chemicals killing Florida birds, fish

Paul said he did not dispute that the president has the authority to take swift and lethal action against an enemy that carried out a significant attack against the United States.

NPR: Senator Launches Lengthy Debate To Block CIA Pick

We already have drones that do most of the work on their own, of course, but the report argues that human control for any lethal action is a vitally important part of the process.

FORBES: Human Rights Group Advocates Ban on 'Killer Robots'

In a major policy speech Thursday, President Barack Obama raised the bar for U.S. lethal action against terrorist groups, saying the U.S. will strike only at those who pose an imminent threat to Americans, rather than at terrorists who threaten U.S. allies and interests.

WSJ: Militants, Chased From Mali, Pose New Threats

Attacking terrorist targets in Africa is not a new trend, in fact a secret order (known as the al-Qaeda EXORD) dating back to 2003 authorized lethal action by JSOC forces against al-Qaeda in Algeria, Mali, Nigeria, and Somalia and Syria so long as JSOC forces sought the tacit approval from the country involved or at least a sign-off from higher up on the American chain of command.

FORBES: Terrorist Safe Havens in North Africa Threaten the United States Homeland

Only prompt action by subway employees two months later prevented clouds of lethal cyanide gas from killing commuters at Tokyo's Shinjuku station.

ECONOMIST: The crazies and their poison