A very informative editorial on nuclear retaliation.

http://www.slate.com/id/2208219


This raises some pretty good questions.

the prime minister is an asshole. the only thing that would do is cause more people to die.

Well, that's assuming he authorizes a retaliation in the letter, which he most likely didn't. The article is saying that if the enemy realizes this, then there is no point in nuclear deterrence.