Why do you feel it is important to establish the authority a team has in the decision-making process prior to a project beginning?

This DB has three parts.
As a manager, you may have employees who are not enthusiastic about working on a team. This could be due to any number of reasons. However, if your organization depends on cross-functional or cross-departmental teams to maximize resources and manpower, the employees will need to not only work on a team but be an active member. When faced with employees who are not willing to be an active member of a cross-departmental team how would you coach the employee to gain their buy-in.
Why do you feel it is important to establish the authority a team has in the decision-making process prior to a project beginning?
When an organization has offices in multiple countries how would you overcome the location and language barriers when creating a cross-functional or cross-departmental team?