You can't get much more liberal than John Kerry is. I mean, he's my candidate, but, I mean, come on.
You learn to rely on a few basic movements and use your voice to the greatest extent possible to convey your emotions. So there was a technical challenge there and a responsibility to create a character from behind the mask.
If one book's done this well, you want to write another one that does just as well. There's that horror of the second novel that doesn't match up.