Short answers, pulled from the story.
The Peace of Westphalia treaty was signed in 1648. It established sovereign states as fundamental units of power and declared that rulers held absolute authority within their own borders.
Immanuel Kant published Perpetual Peace in 1795. This work serves as the intellectual basis for liberal theory which argues states remain institutionally constrained by powerful international organizations like the United Nations.
Alexander Wendt published a pivotal article titled Anarchy Is What States Make Of It in 1992. Constructivists believe the system rests on social constructs including ideas norms and identities rather than objective laws.
Geneva contains the highest number of international organizations anywhere on Earth today. The Palace of Nations in Geneva hosted over ten thousand intergovernmental meetings during 2012 alone.
Feminist International Relations emerged largely from the late 1980s onward following the end of the Cold War. Carol Cohn wrote Sex and Death in the Rational World of Defense Intellectuals in 1988 to claim highly masculinized culture within defense establishments contributed to divorcing war from human emotion.