A liberal theory of externalities?

Unlike exploitative exchanges, exchanges featuring externalities have never seemed to pose particular problems to liberal theories of justice. State interference with exchanges featuring externalities seems permissible, like it is for coercive or deceptive exchanges. This is because exchanges featuring negative externalities seem to be clear cases of the two exchanging parties harming a third one via the exchange—and thus of conduct violating the harm principle. This essay aims to put this idea into question. I will argue that exchanges featuring negative externalities are not unjust in this straightforward way, i.e. because they would constitute an instance of wrongfully causing or risking a bodily or material harm. In fact, unless we are subscribing to particularly demanding variants of liberalism—e.g. perfectionist liberalism—or unless we are exclusively focusing on borderline cases of externalities—i.e. of effects of exchanges hardly to be called externalities—there is no liberal theory of how exchanges featuring externalities are unjust.     

American Psychiatric Association: Position Statement on Firearm Access,Acts of Violence and the Relationship to Mental Illness and Mental Health Services

The American Psychiatric Association, (“APA”), with more than 36,000 members at present, is the Nation's leading organization of physicians who specialize in psychiatry. APA provides for education and advocacy and develops policy through Position Statements. It promotes enhanced knowledge of particular topics relevant to psychiatric practice and patient care through Resource Documents. Since 1993, the APA has developed various positions and resource materials related to firearms and mental illness, incorporating evolving themes as new issues emerge. This paper reflects the APA's 2014 Position Statement on Firearm Access, Acts of Violence and the Relationship to Mental Illness and Mental Health Services.