Discussion Groups / English Usage / January 2004

You have at least four strings to search on, combinations of preemptive
vs. pre-emptive, and defense vs. defence. I'm not sure whether the
hyphen after self is firm.

Under "Preemptive self-defence" the earliest post that Google Advanced
Group Search (the Usenet archives) gives is

    From: Damien Falgoust (dfalgoust@mail.utexas.edu)
    Subject: Re: What About Sodom and Gomorrah???  
    Newsgroups: misc.activism.militia
    Date: 1997/03/17

The earliest post in the Usenet archives using the phrase is dated 1998.

    From: Ergoperson (ergoperson@aol.com)
    Subject: Clinton Parady  
    Newsgroups: alt.politics.usa.congress
    Date: 1998/12/17  
     
    Global replacements and a few simple edits, a parady
    evolves.
     
    -------------
    Republican address to the congress on the Clinton
    affair.

[big snip]

    And mark my words, he will develop weapons of
    mass deception. He will deploy them, and he will
    use them.

It's not a euphemism, of course. It's a joke, a parody, a play on words.
I've also heard "weapons of mass distraction" -- Tony Blair even said
that in public just a day or two ago, and quickly corrected himself.
That one shows up in Google Groups much more recently -- 7 Oct 2002.