(The Indian Express has launched a new series of articles for UPSC aspirants written by seasoned writers and scholars on issues and concepts spanning History, Polity, International Relations, Art, Culture and Heritage, Environment, Geography, Science and Technology, and so on. Read and reflect with subject experts and boost your chance of cracking the much-coveted UPSC CSE. In the following article, Ajay Darshan Behera explains the approaches to the study of international relations.) Global trade war triggered by US President Donald Trump’s tariffs keeps countries on alert, with China on Monday saying it firmly opposes any party reaching a deal with…