The Pakistan War was in many ways the culmination of every major geopolitical fault line in South Asia culminating into a single war. As the War in Afghanistan continued to become more centered on the activities of the Taliban and other terrorist groups in Pakistan, the Pakistani military found itself in a position where cooperating with the United States would add to its own internal instability rather than taming it. Eventually in the fall of 2010, Pakistan's military overthrew the civilian government and began actively opposing the American war effort against the Taliban.
With a Jihaddist backed regime in power in Pakistan, and the very real threat of an unstable nuclear power, a coalition between NATO, China, India, and Russia was formed to promptly neutralize Pakistan's nuclear arsenal.
The War was relatively short, lasting only about five months, and resulting in the complete and total devastation of Pakistan through conventional warfare. The air forces of China, India, the US, Russia, and their NATO allies undertook the most extensive conventional bombing campaign since the Vietnam War, destroying all military and strategic infrastructure within a matter of weeks.
During the War, the US also led several covert operations into Pakistan with Russian Spetznaz and British SAS operatives that eventually resulted in the deaths of the terrorist leader Osama bin Laden. Several other covert activities were led into Iran to supply the green revolution with munitions to eventually overthrow the sitting Mullah regime.
The war was the last major conflict in the middle east that the west was officially involved in until the Flood War, and is widely considered to be one of the bloodiest conflicts of the 21st Century due to the number of civilian casualties.