Existential Threat

Dustbury references a Forbes story about security theater, which uses the term "existential threat", which means what? So I look it up and I find a non-definition on Jargon Database dot com, but then I find a pretty good discussion by Dr. Y on Science Wonk dot com.

Seems an "existential threat" is one that threatens one's existence. Now existence can be a funny term. A man with a gun can threaten your existence. He could shoot you and kill you and you would cease to exist, but your body would still be there, it would still "exist". Likewise, as Dr. Y posits, you can destroy a nation by breaking it up, like Yugoslavia or the U.S.S.R. when the Soviet empire collapsed. Those "countries" ceased to exist, but the nothing actually changed. The land did not vanish. The people were all still there. The U.S.A. went through a horrible civil war, a war that threaten to "destroy" the country. The "country" survived, but only at the cost of half a million lives.

I'm beginning to think that when people use the term "existential threat" they mean that the threat exists. Whether it is actually threatening the existence anything other than our language is another thing entirely.