Red Line

[Dave Wilton]

Use of "red line" to mean a figurative trip wire:

"If he is the real arbiter of Lebanon's destiny, he should have no scruple
about breaking the invisible 'red line' which has deterred direct assault on
the Christian enclaves." Jung-hui Chien, Subject: LEBANON & SYRIA (Sunni
Syrian Conscripts to rebell ?), Newsgroups: talk.politics.mideast,
soc.culture.arabic, 11 Sep 1989.

"...the unmonitored withdrawal of reactor fuel would be a 'red line' beyond
which Washington would be forced to pursue sanctions at the United Nations."
Reuter, "North Korea Dispute Could be near Critical Point," 17 May 1994.

"The Clinton administration had drawn a kind of red line, saying that it was
ready to use force if the North Koreans moved to use that plutonium."
Unnamed questioner, "DoD News Briefing - Secretary Rumsfeld and Gen. Myers,"
23 Dec 2002, http://www.dod.mil/news/Dec2002/t12232002_t1223sd.html

"Rumsfeld addressed reports that there was a 'red line' -- as some news
stories called it -- around Baghdad where local Iraqi commanders could use
chemical and biological weapons." Jim Garamone, American Forces Press
Service, "Coalition on Track, Forces 'Flowing' into Iraq," 25 March 2003,
http://www.defenselink.mil/news/Mar2003/n03252003_200303257.html

I've also seen use of "red zone" to refer to the region around Baghdad. I
assume this comes from the football jargon term for a defense in front of
the goal. Does anyone have info on the origins of "red zone" in football?