It is a combination of things, obviously.
First and foremost,
Jaime and
Mike: their intelligence, their diligence, their commitment, their fairness, and their low tolerance for uncivil debate. The fact that they have encouraged a wide range of opinion and a diversity of participants from the very beginning has been an important factor as well. They see the opinions of middle school students as being as worthy of consideration as those of college professors (which they are) - and the tone has been distinctly egalitarian from the word go. Indeed, they deliberately encourage as wide a range of views as possible. A board on which
Amlord and I can peacefully coexist - never mind work together as members of staff - is doing
something right. This is all part of the vision of two of the most liberal conservatives I've ever met (I
meant that as a compliment

).
The contributors, individually and collectively, would also be a major factor. Many people here are veterans of either contentious flame wars elsewhere or those who grew weary of preaching to the choir on partisan boards. The fact that so many here are interested in
discourse - in reading as well as posting, in
engaging the other participants - is a major key to the success of the site. The members themselves also help "police" the site and many make efforts to reach across the aisle in an attempt to keep the tone civil and even playful, however great the divisions of opinion. Many also help encourage newcomers to adopt a more productive style of debate. Without active, concerned members participating in the climate which the administrators encourage,
America's Debate wouldn't have lasted more than a few months. Many people have found a "home" here - and many friendships have developed, often between those violently opposed ideologically.
Obviously, the rules and guidelines - and their enforcement - are another contributing factor. From something as simple as encouraging correct spelling to something as serious as monitoring hate speech or moderating personal attacks, every aspect of discussion here is directed toward constructive, informative discourse. Looking back at earlier threads here, one can easily see how
America's Debate has evolved, becoming (unlike most discussion boards) progressively
better. One of the main reasons for this is that the rules themselves have undergone almost constant revision, adapting to new situations as they emerge and, hopefully, preventing certain types of behavior which have arisen from reappearing. And, again, the membership has evolved along with the rules. While some have had issues with both the rules and their enforcement, most of those who become "regulars" recognize that the intent is to maintain a higher level of discussion and, at all costs, to keep those discussions as friendly as possible, well-founded, and on track.
The staff which
Jaime and
Mike have assembled would also play a part. As one of the first members to have been coopted onto the members' committee, I can attest to the fact that their intention from the outset has been to keep the staff as politically balanced as possible (for the first few months,
Cyan and I were the moderate to liberal foils to the moderate to conservative admin). While I doubt that either
Jaime or
Mike could allow ideological differences to affect their judgement, they have nevertheless taken the precaution of establishing "checks and balances" even in the structure and selection of the staff as it, too, has evolved. In discussing moderation problems, personal challenges, the development of the site, special projects - in discussing
anything - we try to bear the best interests of the entire membership in mind and make a concerted attempt to be as non-partisan as possible.
Jaime has set an example for the entire staff in terms of moderation: considered, yet swift - and as just and consistent as possible.
The programming of the site itself has played a part in the board's success, too - and here, many thanks are due to
Mike who is constantly adding new features, improving on old ones, and exploring various bells and whistles which will make the user interface more appealing and easy to use - with cool features appearing at an alarming rate. His technical expertise has also enabled him to root out spammers, people attempting to register with multiple identities, and other problems to which such sites are prone.
Finally, I think that the structure of the site (the topic breakdowns and so on) and some of the "content features" have contributed to its success. The scheduled Live Chat sessions, for example, or the encouragement of Casual Conversation (especially things like the pinned introductory threads) - as well as, in my experience at least, a fairly lively PM system - have helped create a sense of community and a way for newer members to familiarize and ingratiate themselves into our ever-growing "village". Even features like the annual awards, the NFL pool, or something as simple as birthday greetings, have helped make this what is probably the most amenable arena for engaging in political debate on the web.
Jaime and
Mike are the geniuses, but we
all make it work.