I did not know that Doug Feith worked on the CWC, but he recounted that experience in this 2012 interview:

I knew President George H. W. Bush a little bit, having worked with him in the Reagan administration. I was responsible for the chemical weapons negotiations and he was very interested in that.

Riley
He cast the tie-breaking vote.

Feith
He had to vote in the Senate as Vice President on the modernization of the U.S. chemical arsenal. He rather remarkably gave some kind of press interview where he said that his mother called him and berated him for that vote and that, in part to satisfy her, he was committing himself to chemical weapons arms control.

We wound up having a debate within the administration on chemical weapons arms control. The State Department generally argued that the way to make progress in an arms control negotiation in the view of some people is to find out what the other guy wants and give it to him. That was not the way we analyzed these things at the Pentagon. Yet we knew that, as the saying goes, “You can’t beat something with nothing.” So when the State Department came in with what they called an initiative, which was basically a retreat on the issue of verification, we needed to say more than “no.” We came up with an alternate initiative.

It was a bold, “anywhere, anytime” inspection regime. One of the biggest problems with the chemical weapon ban is that it is not verifiable in any meaningful sense. So we tried to at least tackle this by saying we would do inspection anywhere, anytime. This was controversial within the U.S. government because some of our own military and intelligence people were unwilling to accept anywhere, anytime inspections of U.S. facilities. We said to the President, “If we’re not willing to tolerate it, then don’t ask for it. But if you’re not going to ask for it, then don’t fool yourself into thinking that you can have a verifiable chemical weapons ban. Then you have to ask yourself, do you want a chemical weapons ban that the United States will adhere to, and the Soviets can cheat without detection? Mr. President, over to you.”

When we were dealing with Ronald Reagan, we found that time after time he came to what we considered to be the right answer on questions of that kind. He did so after debates that lasted months. Anyway, in the course of the chemical weapons arms control debate, I got to know President Bush.

When the Defense Department prevailed in this debate, I was the one who accompanied Vice President Bush to Geneva to present this. I got to know him somewhat. I later decided I wasn’t interested in working for him. I had also just started my law firm, so I was perfectly happy to stay out of the Bush-Senior administration.