Do not let us mistake necessary evils for good.

-C.S. Lewis

One of the most pernicious mindsets used to poison public discourse is the notion that  adopting lesser evils to prevent greater harm somehow sanctifies those difficult choices.  Incarceration may prevent individuals from rending the social fabric of interdependence; but depriving other of their liberty is destructive, and the damage caused can not be considered a blessing.  

It may be comforting to redefine the harm caused to others as "good", but it lures one onto the path of corruption.  In a desire to avoid cognitive dissonance , it becomes easy to proclaim that the admirable ends justify loathsome means, and that loathsome means are now hallowed actions.  With such rationalizations, the concept of virtue begins to warp until "virtue" is indistinguishable with ones own desires.  

The carnage wounds all parties involved; the toxin pollutes indiscriminately.