According to interview guru John Sawatsky, you don't need to be a pit bull named Bruiser to conduct a good interview. In a piece I read so long ago that i can't remember where I put it, he posits that the best interviews, in fact, are about discipline on the part of the reporter, rather than the power differential between interviewer and source. They are about listening, leading the source down the path toward the given goal: staying in control by playing nice.
Which brings up Katie Couric's exchange with Sarah Palin wrt the Supreme Court. Watch how Couric's quiet little follow-up gets the job done: