What happens if you feel you can't express dissent?

Imagine you are in a meeting, and you sense that the group has prematurely converged on a solution.  The leader does not seem to want to hear dissenting views.  What do you do?  The easy answer is to have the courage to speak up anyway.  That's tough though, and it may embarrass the boss.  A one-on-one meeting might be more productive.  Talk to the leader privately.  Discuss how you think several people may have other ideas or alternatives that they are reticent to put forward.  Don't critique the current plan.  That may put the leader on the defensive.  Instead, simply suggest that it might be worthwhile to examine other options, if for no reason then that the discussion may help strengthen the current proposal.  Talk about others who perhaps have ideas that they have not shared.  Suggest that the leader invite a broader discussion.  This type of discussion in a one-on-one meeting with the leader often is a more effective way forward as opposed to direct confrontation in a large meeting.