During the Cold War, India was a leading member of the Non-Aligned Movement -- a group of countries that proclaimed that they would not ally themselves with either the USSR or the US. The reasons were multiple: India has an occasionally volatile 2500-mile border with China, which itself had various interests in conflict with either the US or the Soviets; India was an unhappy legatee of British colonialism and tended toward socialism and proto-communism but retained a parliamentary democracy that helped prevent totalitarianism; India simply had its own dang problems -- high population, poor economics. The effect, however, of being neutral in a dispute between a totalitarian and a democracy is that the totalitarian benefits from your neutrality. After all, for evil to triumph, good men must do nothing.
Today, as it transforms its economy from Third World statism to market-based, and with the death of the Soviet Union, India's most pressing international problems are with Muslim extremists in Pakistan and the imperial aspirations of China. To counter those enemies, India and the US have become allies. And this may end up as Bush's greatest legacy: bringing the US closer to India, which can be a counter to the threat of increasing Chinese military power, a vibrant free-market democracy in the second most populous nation, and a stalwart against Muslim extremism.