Almost everyone I know on a charter school governing board has very good intentions and wants to do the right thing. I often use the quote, they're "the well-intentioned in full pursuit of the irrelevant."
Once in awhile, there's a rogue board member who has his own agenda. This is the reason board member agreements are so important. When a board member steps out of line, it is the responsibility of the board president to point out the provision in the board agreement that addresses the action.
The reason I say it is the responsibility of the board president is because interpersonal problems with board members isn't a valid reason for an executive session. I believe the first step when someone has acted inappropriately is for a one-on-one conversation. Treat the other person as you'd like to be treated; give that person the benefit of the doubt with a gentle correction.
If the conversation between two people doesn't work, there is no choice but to have a discussion amongst the board, in public session. This should be used as a last resort.
To be proactive, every charter school governing board should have an agreement, with expectations and norms. This should be signed at least yearly by every board member and kept on file with the corporate records. This agreement should also be used during the candidate eligibility and interview process.