In the RAFT ordering service within Hyperledger Fabric, the concept of the "Leader" is crucial for the ingestion of new log entries, their replication to other ordering nodes, and managing when an entry is considered committed. In a RAFT-based ordering service, the leader node is responsible for managing the log entries; it receives all client requests, appends them to its log, and replicates these logs to the follower nodes. The leader also plays a crucial role in ensuring that there is a consensus on the order of transactions before they are committed to the ledger. The leader is dynamically elected by the cluster nodes and can change due to network conditions or node failures. This role is pivotal in the RAFT consensus mechanism for maintaining a consistent and reliable ordering service​​.