When leading a discussion on contentious matters, frame the issues in a neutral manner, explain the outcomes required from the meeting and allow your team to work it through. A common mistake is for the leader to speak too much and/or to 'anchor' the discussion, i.e. making it clear what he/she thinks the solution should be. Such an approach stifles creativity (who wants to go against the boss?) and precludes buy-in (there is no ownership of the solution which has been given in a top-down manner). The leader should get the team to generate and debate ideas, keep the discussion on track, encourage participation, periodically summarise and then make a decision.