Nudnik - n. U.S. colloq. Esp. in Jewish usage: a pestering, nagging, or irritating person
There's no question that "healthy debate" is an important part of every serious enterprise. But let's not beat around the Bush. When these characters talk about the need for "debate," they mean one thing and one thing only: They fear Bush won't be forced to take account of opinions and judgments they like and will instead fall back on opinions and judgments he likes.