I suppose there are few theologians I respect as much as I respect Dr. James Leo Garrett, Jr., retired Emeritus Professor of Theology at Southwestern Baptist Theological Seminary. I've spoken before of his impact on my own life and I remain eternally grateful to Dr. Garrett for his careful scholarship, his irenic spirit, and his example of Christ-likeness.
I recently heard the audio of Dr. Garrett's lecture, "Under the Lordship of Christ Through Democratic Process," and was impressed with his approach to the idea of congregational polity. Congregational polity is a tenet of Baptist ecclesiology that needs to be better understood, primarily as it tends to be conflated (in my experience) with American democratic processes instead of with New Testament example. To that end, Dr. Garrett's lecture is most helpful. I do believe that Dr. Garrett's lecture is published in the recent book, Upon This Rock. I also note a 2005 article by Dr. Garrett entitled, "An Affirmation of Congregational Polity."
I believe in congregational polity, though Garrett is correct in noting that the New Testament does not provide an overly-detailed and exhaustive blueprint for the inner-workings of decision making in the church. Mega-churches, for instance, can struggle with how to involve the entire congregation in decision making. Of course, congregational polity requires patience and work. Obviously it would be much easier for a select few to make all the decisions...but it would not be Baptist. Garrett rather humorously (and correctly) points out that dictatorships are always more efficient! But Baptist churches do not (or least, should not) have dictatorships. In fact, one of the great strengths of our polity is the involvement of the people of God in the decision-making of the church.
That being said, I will end with this: congregational polity works best within the context of the Baptist ideal of regenerate church membership. Translation: congregational polity has integrity only when the congregation is a congregation. That is, congregationalism works best when the congregation is an accountable body of believers who are walking together in the gospel and are united in their understanding of what the church is. At least, this was the dominant understanding of congregational polity for the majority of Baptist history.