What is a “doer/dooer/duer” drink?

I just saw a clip of The West Wing on YT. Martin Sheen as the President asked in a random joke for “two doers (?) on the rocks.” He plays an American guy with knowledge of history and culture, especially American and with focus on New England, where he comes from, and with some old fashioned tastes. He said it in a joke, indicating it’s not necessarily something he drank often or expected to get at short notice. And it came on the rocks, indicating it’s a spirit or spirit cocktail. With all that in mind, does anyone know what the drink is? please tell me