"metonymic significance"

[Arnold M. Zwicky]

NYT Magazine, 9/5/05, p. 38, "Political Science" by Daniel Smith:

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The notion that there is widespread "misuse" of science first gained
its force from a series of instances in which administration
officials have... "broken with an unwritten code of scientific
conduct."  Two of these instances... have taken on almost metonymic
significance.
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the instance stands for the whole; the whole can be characterized by
the instance.  clear enough, but the wording is far from everyday.

roughly twenty relevant google web hits, most from lit-crit or
anthropology contexts.

i *think* the usual, and not very accurate, cliche is "talismanic
significance".  but how do you convey this meaning in wording less
jargony than "metonymic significance"?

arnold