Just as likely, it could start over a misunderstanding, computer or human error, as it nearly did in 1995 when Yeltsin was within three minutes of launching an ICBM strike at the United States after Russian early warning systems mistook the launch of a Norwegian rocket for a missile launch. It also nearly happened in 1983 (Google "Stanislav Petrov", an unsung hero of the Cold War who is probably responsible for saving the lives of billions). Sooner or later, our luck will run out unless we demand that our leaders maintain vigilance over the controls and protocols for using these dreadful weapons. I don't believe any rational leader would use them preemptively (notice that I said "rational", which automatically excludes all the neoconservative loons who seem to get a hard-on over their war fantasies).
As for rlange-3, his comments are a typical conservative response to this kind of discussion. Don't think about horrid things like nuclear war. Don't think about global warming. Don't think about children living in poverty. Just go back to your nice, warm, comfortable little world and buy another flat screen TV on your credit card, and trust the adults to worry about the important stuff. Oh, and if things go pear-shaped anyway, then just blame those horrible "liberals" for daring to talk about serious topics and threatening our nice little Leave-It-To-Beaver fantasy world.
I think rlange-3 does make a good point in that not many people will pick up on the deeper ideological issues of films like 'The War Game' just as they don't question the deeper political issues surrounding 'climate change'. There was the fairly clear subtext in the introduction of 'The War Game' that Britain is a greater target for the Russians because of US airbases, for example. There were also quotes from America and the Vatican (both tiresomely predictable liberal targets) which looked like they were taken completely out of context.