Thinking the Unthinkable: Nuclear War between India & Pakistan

Scenario planning was created by Herman Kahn (1922-1983). In the late 1940's he worked at the Rand Corporation, a US military think-tank, where he applied analytic techniques, such as game theory and systems analysis, to military strategy and the possibility of nuclear war. Khan wrote about different nuclear war scenarios. His ideas were so distasteful and upsetting that one journalist, Gerard Piel of Scientific American, coined the phrase "thinking the unthinkable" to describe Khan's work. Khan liked the phrase so much he used it as the title of his next book.
Khan believed that the best way to prevent nuclear war was to avoid blind spots and think through what would happen if war occurred. How would a nuclear war play out? What would be the outcomes? What kind of world would survivors face?
"Thinking the unthinkable" is an exceptionally powerful concept. We don't think about the unthinkable because we find it horrifying, deeply discomforting as it threatens deeply held values, assumptions, beliefs or wishes. Therefore we cannot begin to ask, what conditions would lead to these events occurring? What danger signals would lead me to believe the likelihood of these terrible scenarios is increasing? By refusing to think the unthinkable, we voluntarily create blind spots for ourselves.
What if the US intervention in Afghanistan creates to a series of chain events that destabilized the region, result in nuclear war between India and Pakistan?