While I might agree for now, probably only until I have seen mass deaths caused by a WMD on US soil that is not a nuke, that was not what the US government stated a while back (maybe somebody on freerepublic can find the article). I thought they said that nukes would be the response for any WMD.
Everybody thought the government knew something that we did not and were sending a warning, when that statement was released as offical policy.