What an uninspiring subject. Political Geography takes everything you already know from political science, international law, and history, and tries to relate it spatially or geographically.
It is interesting to note that the subject came to be almost solely due to the Great Game between Russia and Britain in Central Asia. Russophobic geographers tried to influence British foreign policy against Russia by creating bogus fear monger theories, such as Mackinder’s Heartland Theory, which were essentially the development of this field. Then in light of a German threat, the field was expanded to include them. Political Geography is quite literally based on the foundations of hawkish lobbying; although, efforts at legitimizing the field in the 20th century have been more successful.