An ultrasonic surgical instrument, comprising: (a) an end effector configured to actuate from a first configuration to a second configuration, the end effector including: (i) an ultrasonic blade configured to be selectively driven to apply an ultrasonic energy to a tissue, and (ii) an RF electrode configured to be selectively driven to apply RF energy to the tissue, wherein the RF electrode is further configured to measure a tissue impedance of the tissue engaged by the end effector; (b) a shaft assembly projecting proximally from the end effector; (c) a body projecting proximally from the shaft assembly, wherein the body includes: (i) a first ultrasonic energy input operatively connected to the ultrasonic blade, wherein the first ultrasonic energy input is configured to be selectively actuated from a first unactuated energy input state to a first actuated energy input state, (ii) a trigger operatively connected to the end effector and configured to selectively actuate the end effector from the first configuration to the second configuration, and (iii) a trigger input operatively connected to the trigger, wherein the trigger input is configured to be actuated from an unactuated trigger input state in the first configuration to an actuated trigger input state in the second configuration; and (d) a power controller operatively connected to the ultrasonic blade, the RF electrode, the first ultrasonic energy input, and the trigger input, wherein the power controller is configured to direct activation of at least one of the ultrasonic blade or the RF electrode according to a predetermined drive function based on the tissue impedance, the state of the first energy input, and the state of the trigger input, characterised in that: the power controller is further configured to determine whether the measured tissue impedance is below a lower impedance threshold, above an upper impedance threshold, or intermediate between the lower and upper impedance thresholds, wherein a measured tissue impedance that is below the lower impedance threshold correlates to an electrical short. (a) an end effector configured to actuate from a first configuration to a second configuration, the end effector including: (i) an ultrasonic blade configured to be selectively driven to apply an ultrasonic energy to a tissue, and (ii) an RF electrode configured to be selectively driven to apply RF energy to the tissue, wherein the RF electrode is further configured to measure a tissue impedance of the tissue engaged by the end effector; (i) an ultrasonic blade configured to be selectively driven to apply an ultrasonic energy to a tissue, and (ii) an RF electrode configured to be selectively driven to apply RF energy to the tissue, wherein the RF electrode is further configured to measure a tissue impedance of the tissue engaged by the end effector; (b) a shaft assembly projecting proximally from the end effector; (c) a body projecting proximally from the shaft assembly, wherein the body includes: (i) a first ultrasonic energy input operatively connected to the ultrasonic blade, wherein the first ultrasonic energy input is configured to be selectively actuated from a first unactuated energy input state to a first actuated energy input state, (ii) a trigger operatively connected to the end effector and configured to selectively actuate the end effector from the first configuration to the second configuration, and (iii) a trigger input operatively connected to the trigger, wherein the trigger input is configured to be actuated from an unactuated trigger input state in the first configuration to an actuated trigger input state in the second configuration; and (i) a first ultrasonic energy input operatively connected to the ultrasonic blade, wherein the first ultrasonic energy input is configured to be selectively actuated from a first unactuated energy input state to a first actuated energy input state, (ii) a trigger operatively connected to the end effector and configured to selectively actuate the end effector from the first configuration to the second configuration, and (iii) a trigger input operatively connected to the trigger, wherein the trigger input is configured to be actuated from an unactuated trigger input state in the first configuration to an actuated trigger input state in the second configuration; and (d) a power controller operatively connected to the ultrasonic blade, the RF electrode, the first ultrasonic energy input, and the trigger input, wherein the power controller is configured to direct activation of at least one of the ultrasonic blade or the RF electrode according to a predetermined drive function based on the tissue impedance, the state of the first energy input, and the state of the trigger input,