Geo-replication of large Internet services is increasingly deployed for better data locality and fault tolerance. Maintaining consistency across datacenters is expensive and requires wide-area communication. This renders current solutions to either settle for weaker forms of consistency or suffer from large delays. In this paper, the authors present Message Futures, a strongly consistent concurrency control manager with low commit latency to ensure mutual consistency of replicas across datacenters. By judicial message passing of relevant information and at opportune time intervals, Message futures can also enforce different priority levels of access, where each datacenter experiences a commit latency relative to its priority.