Specifically: chemical gas attacks.
— Jim Geraghty (@jimgeraghty) November 23, 2015
Once we had boots on the ground, anyway. You see, we used to have this policy: nuclear, biological, and chemical weapons were all classified as something called ‘weapons of mass destruction,’ or WMDs. If you used a WMD on us – or our buddies – we would respond in kind. And since it is American policy to only maintain war stocks of nukes, well… a lot of people figured out that it probably wasn’t safe to use any of that stuff while American troops were in the vicinity. Bad luck, in an actuarial table sort of way.
But that was in the Good Old Days.