An electrosurgical instrument can comprise a handle, a shaft, and an end effector, wherein the end effector can be rotatably coupled to the shaft by an articulation joint. The instrument can further comprise a drive member and the articulation joint can comprise flexible support members which can be configured to support the drive member. The instrument can further comprise supply wires electrically coupled to electrodes in the end effector and a wire tensioning device configured to prevent the supply wires from accumulating slack within the articulation joint. The drive member can comprise a plurality of flexible layers wherein some of the layers can be comprised of an electrically insulative material and other layers can be comprised of an electrically conductive material which is in electrical communication with a cutting member in the end effector and/or electrodes positioned within the end effector.