A thermal surgical instrument having a system to control the delivery of power from an energy source to an active element located on a tip. The system for controlling delivery to the tip may include a control algorithm which uses one or more measurements, such as tip current, SWR, and rapid changes in reflected power, to manage power without affecting cutting efficacy, and in a manner that may be imperceptible by a surgeon. The system may utilize a state machine to determine the current environment in which the tip may be in. Power delivered to the tip may be selectively managed according to a fixed power index or a repeatedly executed power profile.