Using VB, you can move posts, and create their own threads, if necessary. So, per se, I start accusing the Americans of being after Oil in Iraq in this post, it can be shipped off to the "Political" forum, and I can be dissected there.
As for the behavior spilling out; It happens. Depends upon how mature your crowd is. In another forum I used to frequent, they had a political debate forum, and while, for the most part, it was fairly well behaved, several threads, which consisted of slights directed against the other party, ended up being made. HOWEVER, the average age of the poster on those forums was about 18, with a low of 12. They were not the most mature people on the face of the earth.
But, Mel seems to intend for this forum to be on the subject of Sniping only. While a forum on politics will aid in building a strong community and following for the site, it will not make things easier. People will develop issues, and there will be drama, drama, DRAMA. But, that uses my previous experience in the aformentioned forums as a base, so it could be different here.
To summarize; You'll probably end up with some issues, but with a bit of maturity (And perhaps a heavy hand from moderation), these issues can easily be laid to rest.