Prior to allied air strikes, troops loyal to Muammar Qaddafi were quite close to crushing the popular uprising in Libya and massacring the opposition. By any reasonable reading of international human rights law, Qaddafi is culpable for human rights crimes on a grand scale, but why is it an American responsibility to respond?
Before World War I, international law was quite clear that sovereigns were free to do whatever they chose to their citizens to maintain order and control, as long as their actions did not affect conditions in neighboring states.
Gradually, in the first half of the 20th century, this principle came down. This began after World War I with the creation of institutions like the International Labor Organization, whose core principles compel member states to guarantee freedom of association and by implication guarantee free speech.
The Holocaust and Nuremberg Trials ended the notion that national governments are compelled by international law to turn a blind eye when other national governments inflict atrocities. Over the past seven decades, governments of all stripes have articulated an elaborate web of international human rights law with limited remedies. The latter includes international courts and extraterritorial jurisdiction for domestic courts to bring to justice deposed leaders who commit crimes against humanity.
However, the pressing question is when do governments have a right and responsibility to intervene militarily against the actions of other governments that violate international human rights law, as is the case with Qaddafi.
Neither the United States nor an assembly of allies with comparable resources can be expected to police the world. More important, no national leader or legislature, under emerging international law has the wisdom or right to assume that authority.