The friends one keeps is generally a good indicator of the person. The same is doubly true of states and their ruling regimes. Its not a coincidence that autocrats like Hugo Chavez regularly praises the Castros in Cuba or Ahmadinejad in Iran. Democracies, for their part, run together as well, the North Atlantic Treaty Organization for one.
Thus, the United States' backing of a country like Pakistan (to name but one) has always been of peculiar interest to me. A country always one step away from a return to military dictatorship. There are others to be sure, but none where the U.S. has an active conflict a neighboring country.
The "partnership" (if it can be called that), to my understanding, started during the Cold War as the world divided between the right-leaning countries and left-leaning countries (although supposedly between multi-party democracies and one-party autocracies, the truth is always so much more complicated). Pakistan had become a partner/client of the United States to good effect in the 1980s when it became a conduit for support for mujahid rebels fighting the Soviet Union in Afghanistan. By then it seemed an unshakable bond, though one forged not by two democracies but by a democracy and a military.
For its part, India, though officially neutral (the Non-Aligned Movement), had typically been leaning towards the Soviet Union and dominated by a succession of elites associated with the earlier independence movement.
Then there's China, once an erstwhile supporter of the Soviet Union by the 1980s it had struck its own path. Its political system needs no introduction, a one-party state not emphasizing workers' communism but the righteousness of the Nation (who happen to be composed of workers among others).
Fast forward to the post-11 September 2001 world. China has been on a steady rise, much to India's (and the Southeast Asian nations) chagrin. India is beginning to rise too. China recognizing this and recognizing the importance of geography, most certainly wants to constrain India's growth. Partnership with Bangladesh. Partnership with Pakistan? Oh yes, as the Washington Post finds (Pakistan courts China as relations with U.S. grow strained).
The bin Laden raid earlier this year has become a rallying call for anti-Americanism in Pakistan. Ruling elites have opportunistically harnessed this sentiment and the infringement upon Pakistan's sovereignty to try and partner Pakistan with China. But why?
First, the U.S. routinely makes noise about the Pakistani's state's corruption, lack of political will in dealing with Islamist extremism, and lack of true democracy. China has no qualms about these items, invest in the Sudan, Burma, and other states of a less than savory nature. To be sure, the U.S. invests in Saudi Arabia but at least there's noise about it (at least an acknowledgment).
Second, the Pakistani government recognizes the warming ties between the U.S. and India. Not least of which is the U.S.-India Nuclear deal (Council on Foreign Relations). Not wanting to be left in the lurch, the Pakistani government is the first out of the bed and courting the one-party, non-democratic, Han nationalist economic behemoth that is China.
Despite the weariness of China's officialdom with Pakistan, I doubt it will last long. The relationship between the U.S. and Pakistan has clearly deteriorated, few in the U.S. would be sad to see Pakistan go. India will be happy to see the one-sided partnership end, especially if it believes the U.S. will continue to warm.
However, the long-term implications of a China-Pakistan partnership is significant for both India and the United States. The inevitable return of law and order to Pakistan, whether under a democracy, or more likely a Islamist-military autocracy, would pave the way for safe Chinese investment along the Karakoram highway and from there further access to the Indian Ocean. And from there, the natural resources that it and India, both desperately crave in the Middle East and East Africa.
By developing other "coaling stations," in the Alfred Thayer Mahan sense of the word, in Burma or Bangladesh and China gains the ability to surround the Subcontinent.