Nuclear Apocalypse and the Letter of Last Resort

This is the first time I've seen this position articulated so clearly. I thought I was alone in seeing that paradox.

If Brown orders the assault, an interesting prospect, though thoroughly evil, is that he could take advantage of the circumstances and eliminate all of Britain's enemies - not just the ones that fired on them.

On the other hand, if the weapons have to be fired, perhaps they should be fired at all the other weapons that cannot easily retaliate.

It's scary that this capability still exists. Who's up for funding the space program?

"On the other hand, if the potential foe thought that we might not retaliate once the threat served no purpose—that retaliatory "deterrence" would, in essence, turn out to be a bluff—it would encourage those disposed to strike first to cause a nuclear holocaust without fear of reprisal. We had to threaten genocide—and convince people we meant to carry out our threat—in order to prevent genocide."

Well, that's what that letter is about. Not having to build such behaviour into the system while remaining ambiguous about the threat.

While I recommend everyone carry on living with their lives, I see no reason to believe this threat is not real. Which other weapons in history have failed to see use? (?)