Get real, the idiots who put this together were advocating first strike. Rummy would not be upset if this was about using nukes in defense.
When we got the best conventional forces in the world, it takes an idiot to encourage the development of nukes by the rest of the world.
Its been U.S. policy for at least 25 years (that I know of, maybe longer) that we will NOT rule out first use of nuclear weapons. Jimmy Caht-ah threatened Iran in '79. Saddam was also warned prior to the Gulf War that use of any WMD on his part (e.g. chemical weapons) could draw a nuclear response, and Clinton re-iterated this warning during his term, around '96 I think.
I'm confident that no sensible person here doubts that Rumsfeld is in total agreement that the maximum deterrent effect of our nuclear arsenal is acheived by reserving the right to employ them in response to the use of non-nuclear WMDs, or other genuninely extra-ordinary military circumstances.
Not so. They were postulating scenarios where the threat of a nuclear response would be a deterent. What has got a lot of anti-nuclear leftists upset if that they say it "lowers the bar to the use of nuclear weapons." To take that arguement to the extreme, why don't we just build a nuclear arsenal with only city buster 10 megaton weapons? Oh, those are so terrible we'd never use them!! Bottom line, the US is more secure with a mix of strategic AND tactical nuclear weapons.