India will emerge as the key Eurasian pivot state because of its effect on relations between the United States and China. To effectively deal with India, American policymakers must understand Indian geography and geopolitics throughout its long history. In particular, Indian geography is the story of invasions from a northwesterly direction, and India's strategic challenges still inhere in this fact. Afghanistan, in Indian eyes, is not part of Central Asia but part of the Indian subcontinent. Afghanistan is linked organically to India on account of the record of empires past. This organic connection to India is also true of Central Asia and Iran. As for Pakistan, it is seen by Indians as the modern-day residue of medieval Muslim domination over India. As the India-Pakistan dispute attests, nationalism is young and vibrant in the subcontinent, as it was in early modern Europe. The India-China rivalry, unlike the India-Pakistan one, is far less emotional because it is not borne of historical grievances. India is quietly testing the United States in Afghanistan, to see to what extent America will remain as a great power in Eurasia.
As the United States and China become great power rivals, the direction in which India tilts could determine the course of geopolitics in Eurasia in the 21st century. India, in other words, looms as the ultimate pivot state. But even as the Indian political class understands at a very intimate level America's own historical and geographical situation, the American political class has no such understanding of India's. Yet, if Americans do not come to grasp India's age-old, highly unstable geopolitics, especially as it concerns Pakistan, Afghanistan and China, they will badly mishandle the relationship.