When one watches a debate, he or she expects a certain level of preparedness on the part of both the candidates.  We as viewers understand that these candidates have talking points and not everything is really 'off the cuff'.  A recent article from The Guardian reveals that the level of manipulation that goes into a presidential debate is a lot higher than one might think.

"Under this elaborate regime, the candidates 'aren't permitted to ask each other questions, propose pledges to each other, or walk outside a 'predesignated area.'' Worse, "the audience members posing questions aren't allowed to ask follow-ups (their mics will be cut off as soon as they get their questions out). Nor will moderator Candy Crowley.'The rules even "forbid television coverage from showing reaction shots of the candidates'."

Before the debate last thursday, both the Romney and Obama camp's agreed to a 21 page memorandum that stipulated the very specific and technical rules (including where each candidate could stand and how they were to adress one another).  The goal of this high level of manipulation?  Under these rules neither candidate can ever really be surprised.  

This all really began in 1992 in the first Town Hall style debate between George H.W. Bush and Bill Clinton.  In that first debate no one had established many rules and everything was new.  Questions came genuiniely from the audience and were not prescreened.  During this debate Bush seriously bungled and awkwardly worded question from the audience and it became clear to both Republicans and Democrats that they did not want their candidates to be so exposed.  George Farrah explains how,

"a private corporation was created by the Republican and Democratic parties called the Commission on Presidential Debates. It seized control of the presidential debates precisely because the League was independent, precisely because this women's organization had the guts to stand up to the candidates that the major-party candidates had nominated. And instead of making public these contracts and resisting the major-party candidates' manipulations, the commission allows the candidates to negotiate these 21-page contracts that dictate all the fundamental terms of the debates."

So that's where we're at today.  These supposedly intimate and reavealing debates are as highly manipulated as the rest of the capaign process.  You can read the full article from which the quotes above are pulled here.

The following is a list of the best three rules listed in the 21 page memorandum.  You can access a complete breakdown of the rules here.

"[T]he Commission shall take appropriate steps to cut-off the microphone of any...audience member who attempts to pose any question or statement different than that previously posed to the moderator for review."

"Each candidate may move about in a pre-designated area, as proposed by the Commission and approved by each campaign, and may not leave that area while the debate is underway"

"The candidates shall not address each other with proposed pledges."