A lot is being said on the blogosphere lately about degrees of inclusiveness or exclusiveness in the Southern Baptist Convention, and how this relates to the unity of the Body of Christ.
See Wade Burleson (and comments) here, here , here, and here; Nathan Finn here; Bart Barber here and here, and Jeremy Green here.
From my point of view, unity in the Body of Christ at large is a more important concern that "trumps," if you will, unity in the Southern Baptist Convention, or any other denomination or Christian group, for that matter. Our unity in the Body of Christ, however, does not depend on everyone else "crossing every ‘t’ and dotting every ‘i’" just like we do. I recognize that my understanding of the Word of God is imperfect, and that, as a result, I am not always going to see eye to eye with other sincere brothers and sisters in Christ, who may well love the Lord and his Word just as much as I do. But this does not keep me from loving them, accepting them, fellowshipping with them, and cooperating with them in ministry.
However, the Body of Christ is also very big and very broad. This fact makes it so that it is not always practical nor desirable to directly cooperate with every member of the Body of Christ in every ministry project. Out of a desire for practical stewardship of the Kingdom resources God commends to us as His children, we sometimes form "strategic alliances" in order to more effectively do the work He has given us to do.
I believe the Southern Baptist Convention, and the Cooperative Program, is one such "strategic alliance." However, I believe it is an error to view the SBC or any other grouping of Christians as a microcosm of the Body of Christ at large. I believe we commit the sin of schism whenever we treat the members of one grouping of believers as more authentic or legitimate members of the Body of Christ than another, just because of the grouping with which they happen to affiliate.
Within any "strategic alliance," however, there are pragmatic reasons that lead us to do things the way we do them. We join together, for example, in order to sponsor an orphanage. And we look for other believers who have similar ideas in order to better work together in sponsoring the orphanage. We don’t look to partner with those who have no particular interest in orphanages. Neither do we look to partner with those who have radically different ideas from us regarding how orphanages should be run. However, we are open, to a certain extent, to new ideas, and "thinking outside of the box," but not to working with people whose "core values" are too much in conflict with ours. All in the interest of doing a better job with the orphanage.
The "ministry project package" we as Southern Baptists work together to support is obviously a whole lot more complex than sponsoring an orphanage. It is for this reason that we need conventions, and messengers, and trustee boards, etc. As a group, we must agree, through democratic processes, on how we are going to make the best use of the economic, human, creative and spiritual resources we all contribute to see accomplished the various ministry projects we have joined together to accomplish.
Sometimes, this process brings to light the reality that, in the interest of doing a better job, and moving forward with a reasonable amount of agreement, it is best that some members of the Body of Christ find other "ministry project support groups" with which they can better collaborate. But this does not mean that we begin to treat these brothers and sisters as less authentic or legitimate members of the Body of Christ, just because they do not see eye to eye with us regarding the administration of our particular ministry project. We allow them to go their way, but continue to love them, continue to accept them, continue to fellowship with them, and even remain open to the possibility of cooperating with them, whenever circumstances warrant a strategic cooperation in order to get a ministry project for which we share a common interest or commitment accomplished.
Those who deny the faith, and who fall into heresy that would lead to question even their membership in the Body of Christ at large, are a whole different story. With these, we are bound by Scripture to point out the error of their ways, and to exclude them from fellowship.