Ken Fields is attempting to answer the question of why a church ought to be a part of a fellowship of churches. He even brings a weighty voice from the past to his aid. I'm not convinced. Hopefully, the conversation will dredge up something worthwhile though.
Here's some raw opinion. Associations are to groups of churches what programs are to local churches. Local churches create evangelism/discipleship/youth/women's/men's/yaddayaddawhatever programs to provide a magic bullet—a simple solution to a difficult, painful task of building up one another in the body of Christ. Programs are relatively pain-free, un-dirty mechanisms that help us feel like we're doing the work of the ministry without getting too involved in one anothers' lives. The last thing we American Christians want to do is invade someone's personal space, or worse yet, have our own space penetrated.
Church fellowships or associations are no different. We want a nice, neat statement of faith and some black/white lines of separation that will keep the rank-and-file churches in line without anyone actually having to expend any real effort to invest spiritually and emotionally and energetically in one another. We'll have our conferences where we'll get together for three days and hear some preaching and cheer on the missions agency and pass a few resolutions on somebody else's problems (and watch one anothers' heads get grayer and balder). Then we'll go home for 11.9 months and function independently again. If there's a problem (a church joins the SBC, hires a female associate pastor, or puts TNIVs in the pews), we do what democracies do—we vote and throw the bums out. Simple. Quick. Clean. Painless (relatively).
Is that supposed to be attractive? Is there a better alternative somewhere that is actually functioning proactively? I'm wondering if the regional (secular) accreditation models for colleges and universities might not be a better model—requiring intense self-study, statements of mission, specific, quantifiable goals, and outside accountability. If you really want an association that fosters church health, wouldn't that be more helpful?
Not that such a model would be a good idea either. Not that I know anything, for that matter.