The four enduring U.S. national security interests are security, prosperity, international order, and values. Looking first at values first due to the understandably high interest in the unspeakable human atrocities taking place in Syria currently. This how the 2015 National Security Strategy addressed this sub topic of values. Bold areas are my emphasis.

https://www.whitehouse.gov/sites/def...y_strategy.pdf

Prevent Mass Atrocities
The mass killing of civilians is an affront to our common humanity and a threat to our common security. It destabilizes countries and regions, pushes refugees across borders, and creates grievances that extremists exploit. We have a strong interest in leading an international response to genocide and mass atrocities when they arise, recognizing options are more extensive and less costly when we act preventively before situations reach crisis proportions. We know the risk of mass atrocities escalates when citizens are denied basic rights and freedoms, are unable to hold accountable the institutions of government, or face unrelenting poverty and conflict. We affirm our support for the international consensus that governments have the responsibility to protect civilians from mass atrocities and that this responsibility passes to the broader international community when those governments manifestly fail to protect their populations. We will work with the international community to prevent and call to account those responsible for the worst human rights abuses, including through support to the International Criminal Court, consistent with U.S. law and our commitment to protecting our personnel. Moreover, we will continue to mobilize allies and partners to strengthen our collective efforts to prevent and respond to mass atrocities using all our instruments of national power.
They authors certainly got the strategic context right, not only is this slaughter an affront to our humanity, it is creating a set of second and third order security issues. The mass migration is creating security challenges well beyond the borders of Syria, and the situation is creating an opportunity for extremists to exploit in ways we probably haven't seen fully manifest yet.

Is this is a case of strategic under reach on the U.S.'s part? Where do we even stand right now in regards to policy as it relates to Assad's and Russia's deliberate assault on civilians? Are we being wise to stay disengaged from preventing further atrocities (establishing no fly zones, safe zones, drawing red lines), or strategically foolish?