The debate between Henry Kissinger and Anne-Marie Slaughter about intervention in Syria rests on interpretations of sovereignty and world order that are more complex than popularly depicted. By properly contextualizing sovereignty and intervention in the world system, we can come to a better understanding of what is at stake in the current debate. Post Cold War interventions are part of a great continuum of intervention that goes back at least several centuries.
Kissinger begins by noting the role that the Treaty of Westphalia allegedly played in putting an end to Europe's wars of religion, and goes on to suggest that humanitarian intervention in the Middle East is undermining the norm of state sovereignty:
The modern concept of world order arose in 1648 from the Treaty of Westphalia, which ended the Thirty Years’ War. In that conflict, competing dynasties sent armies across political borders to impose their conflicting religious norms. This 17th-century version of regime change killed perhaps a third of the population of Central Europe. To prevent a repetition of this carnage, the Treaty of Westphalia separated international from domestic politics. States, built on national and cultural units, were deemed sovereign within their borders; international politics was confined to their interaction across established boundaries. For the founders, the new concepts of national interest and balance of power amounted to a limitation, not an expansion, of the role of force; it substituted the preservation of equilibrium for the forced conversion of populations.
While Kissinger's conclusions are very reasonable, the problem is that interventions in the Middle East represent the endpoint of a spectrum of intervention that the United States substantially contributed to with Cold War actions many realists supported. Furthermore, there's also a big empirical problem with the Westphalia-centric interpretation advanced in the op-ed.
First, in a critique of the then-dominant trend of New Medievalism, Lt. Col. Michael Phillips observed that Westphalia was more a metaphor for an at best imperfectly observed world order than a transformative shift in international relations. The treaty itself was silent on the concept of sovereignty, and served only to codify an informal set of arrangements that had already evolved in Germany. More relevant to the balance of power in the oft-idealized pre-Napoleonic European system was the political, financial, organizational, and military difficulties involved in levying decisive war. Warfare before Napoleon is so distant to us as to be alien--a time when the public had little to do with the making of war and conscripts could not biovac near forests lest they desert. Certainly, aggressive men and women existed, but lacked the means to realize their dreams of domination. European warfare in the Americas, however, was waged as if the Thirty Years War never ended. Women and children were targeted, crops and settlements were laid to waste, and irregular forces, pirates, and militias were decisive combatants. Wars in the Americas were wars of annihilation.
As would be demonstrated during the 19th century, intervention in the international system came to take several divergent forms. First, intervention in internal affairs was countenanced when a given state's ideology made it threatening to other actors. Revolutionary France was the Iran of its era, never fully trusted because of its fanaticism, ideological crimes against its own citizenry, and desire to export its ideology abroad. Second, intervention against transnational irregular actors--often in defiance of sovereign boundaries--occured because of the threat pirates and bandits posed to travel and commerce. These actors were viewed as criminals and enemies of all mankind. Finally, non-European powers that mistreated Europeans or populations Europeans were sympathetic to were targets for humanitarian intervention.
During the 20th century the Nazis and Soviets forced a merger of all three categories of intervention. Enemies that sought to wage global ideological war, who inverted Clausewitz--as Lenin did-- to conceptualize politics as war by other means had to be fought everywhere. As Dan has observed, these struggles were if anything much more invasive than the drone wars. The US and Britain routinely violated neutrality and sovereignty, assaulting Iceland to deny it to the Nazis and invading Iran to logistically support the Soviets. The US rightly regarded the Nazis and Japanese as war criminals, but did so in a manner that legal circles viewed with a skeptical eye.
During the Cold War, this logic was taken to another extreme through covert operations against governments and movements deemed to be sympathetic to Communism. It is easy to condemn such activities today, but it is worth noting why they were undertaken. The United States had internationalized its national interest, viewing Communism itself--a borderless ideology--as a national security threat. Hence Soviet influence in states once seen as peripheral to international security became probable cause for viewing these environments as battlefronts. Some of these interventions--particularly in Europe--were justified. Others were tragic failures with devastating humanitarian consequences. It is also interesting to observe that the tools being proposed for intervention in Syria--air and weapon support to rebels--are Cold War vintage. Countless movements--most notably the Cubans and the Contras--were supported by private American air forces and/or weapons support, enabling operations in environments the United States did not view as important enough to devote ground troops to.
Today we have come full circle. Post-2001, authoritarian states are simultaneously viewed as breeding grounds for dangerous ideologies, humanitarian criminals, and supporters of threatening irregular actors. Arguments about US policy towards those states blur all three categories of intervention justification together into a formless blob. While we live in a world that is in some respects safer than ever, debates about intervention still sit implicitly within the framework of global war. It made sense to consider Fascism and Soviet Communism--idious ideologies backed by overwhelming military and political power--mortal threats to international order. But does what happen "over there" really matter "over here" in the same way today? It is difficult to argue that the same relationship exists, but many implicitly do when discussing authoritarian states in international security.
A more difficult problem for sovereignty is the threat posed by transnational groups with absolute aims. Their aims in and themselves may not be strategic threats to the United States, but they certainly pose tactical threats in the form of mass-casualty attacks. The United States usually acts in cooperation with partner states in launching airstrikes and ground raids, but has acted unilaterally when circumstances demand decisive and preemptive operations. When not launching kinetic strikes, the United States has also taken on sovereign responsibilities rightfully performed by host governments in an effort to build host nation capacity. While kinetic strikes pose some risk of blowback, capacity-building arguably poses a moral hazard by enmeshing the United States in the domestic politics of local actors who see Uncle Sam as a walking ATM. When the US tries to make unruly local clients reform, it only deepens American involvement in their domestic politics and further threatens their sovereignty.
The problem is not simple and should not be viewed as "drones bad" and "foreign aid good." Rather, it's a problem of how far the United States can go in managing threats that emerge from troubled states without either making those threats worse or making the US another party in a local civil war or violent elite dispute. Whether firing Hellfire missiles or delivering aid, the US is becoming an actor in a political system it is not institutionally well-equipped to understand or alter. How this problem will be resolved is an important question for 21st century security.
We are still struggling to figure out how we will manage our own national security without either threatening others' sovereignty or performing sovereign responsibilites that they have, for domestic reasons, failed to exercise. While precedents exist in 19th and 20th century history for American diplomatic, political, and military efforts to create domestic security either by intervening in the Western hemisphere or globally, our situation is in many ways unique. The anarchist wave of terrorism was not as cohesive as al-Qaeda and Affiliated Movements (AQAM) are today and lacks AQAM's global reach. It is difficult to see how America could have avoided striking into Pakistan to kill or capture Osama Bin Laden, a move criticized by international organizations as a violation of sovereignty despite the manifold opportunities Pakistan had to bring him to justice. History is important, but there is a limit to how much historical context can shed light on a political-military problem.
To answer the title question: no one lost Westphalia, because Westphalia is a useful myth for international relations theorists seeking a shorthand for systemic change in the international system. Drones didn't kill Westphalia, and Libya--while injurious to sovereignty--has really principally demonstrated that dictators in coastal regions without nuclear weapons, Russian-supplied integrated air defense systems, or basing agreements with the United States Navy might do well to explore alternative career options. But beyond Syria polemics, the real challenge of sovereignty lies in moving beyond the framework of global ideological war that World War II and the Cold War set in place. A different international environment requires a course correction towards security policy inclined, as a rule, towards skepticism on whether or not local security problems have international implications.