We consider the challenges of supporting collaborative decision making and applications requiring coordinated interaction in mobile ad hoc networks. This environment makes group coordination difficult due to relatively high packet loss and the presence of a continuously evolving network topology that leads to a changing set of participants. We describe and evaluate an application-level mobile reliable broadcast protocol (M-RBP) that provides applications with network characteristics well-suited to supporting coordinated interaction, such as reliable broadcast with data consistency and global ordering. The protocol is time-, rather than event-driven, providing it with unique, deterministic operational characteristics that can be verified in a relatively straightforward manner. 2006 Elsevier B.V. All rights reserved.