Cloud computing's ubiquitous infrastructure-as-a-service (IaaS) model has enabled a broad range of enterprise organizations to roll out online services at low cost. Cloud's multi-region support allows computational resources to be instantiated from different data centers around the world, enabling new classes of geographical-scale (or 'geo-scale') applications. State machine replication (SMR) is the de facto standard for building highly scalable and available distributed applications and services. SMR replicates a service across a set of nodes, and executes client operations on the replicas in an agreed upon total order, ensuring consistency of the replicated state. The problem of determining a total order reduces to one of consensus.