Geopolitics, at its core, examines how geography shapes international politics, power distribution and security dynamics. One enduring idea is geographer Halford Mackinder’s “heartland” theory, which situates Eurasia as the central arena of global power competition.

In 1904, Mackinder argued that the vast land mass of Europe and Asia – what he called the “world island” – contained a pivotal core, the “heartland”, rich in resources, population and strategic depth. His dictum – “Who rules Eastern...