Could you specify whether you want answers as percentage probability, probabilities, odds, or expected number of launches? My answer was intended as a percentage
I just used the standard less-wrong probability poll.
http://wiki.lesswrong.com/wiki/Comment_formatting#Probability_Poll
edited the comment to include the description.
India vs. Pakistan: the nuclear option is dangerously close, and nobody seems to want to prevent it
http://qz.com/541502/a-nuclear-war-between-india-and-pakistan-is-a-very-real-possibility/