I think that it is wholly inappropriate to think of another human as an "enemy". By definition, as human, to place the title "enemy" is to term them, the other and the opposition - thus tagging them as irredeemable, just like we do with corporal punishment and death row inmates. To take it a step further and to actually kill this person (in the name of whatever "good") is to first, play god and second to completely deny their humanity. What is the difference between protecting my human, biological brother and feeling the need/requirement to protect a human, non-biological brother if we can assume that everyone is someone else's "brother/sister." The labeling of "human" (a thing which all living homo sapiens are deserving of)is the most validating of terms. Conversely, terming one as "enemy", the most invalidating, similar to how we treat people with handicaps. Invalid.

Who is my brother?