Democracy divides a team more because people usually agree with the loudest voice, not with the best idea. The leader might not have the best idea, but he's more likely to pick a good idea provided by the team if he's given the time to properly think them through.
You don't have to silence the opposition, anyone can do with some advice from time to time. If a choice is made, however, either accept it or leave. Don't hold grudges that will eventually grow into holding a team back.