In an increasingly interconnected world it has become hard to say what actually is so special about the state, and why there would be duties of any sort that apply among fellow citizens, but not among those who do not share a state. This study explains how dealing with this problem has become inevitable; discusses the most promising accounts of the normative peculiarity of states (in terms of coercive structures), and, finding some fault with these specific accounts (which are due to Michael Blake and Thomas Nagel), offers a modified version of this approach in terms of coercive structures.
Risse, Mathias. "What to Say About the State." KSG Faculty Research Working Paper Series RWP06-008, February 2006.