Ground zero

[Peter A. McGraw]

A question for the word sleuths on the list.

"Ground zero" has been around a long time, but until this election I heard
it only as the designation of the exact point where a nuclear bomb actually
lands.  (O.k., I wouldn't swear that I never heard it extended to refer to
a conventional bomb, maybe even other kinds of explosions, such as the
eruption of Mt. St. Helens.)

In this election, a new meaning has suddenly (at least for me) sprung up,
with all the media using "ground zero" to indicate a geographical entity
(state, county, region, whatever) whose votes are crucial to the outcome of
the election, or which is the focus of intense media and party attention
because its votes are seen to be crucial.  I don't quite understand the
connection with an explosion: has there been some intermediate stage in
this development that I've missed?  Has anybody heard or seen this latest
usage before the current election?

Peter Mc.
(Writing from Oregon, which didn't turn out to be "ground zero" after all.)

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                               Peter A. McGraw
                   Linfield College   *   McMinnville, OR
                            pmcgraw at linfield.edu