A surgical instrument which has override protection when excessively thick tissue is attempted to be clamped between opposed jaws of an end effector is disclosed. The instrument includes a frame, a shaft extending from the frame, an end effector connected to the shaft distal end which includes movable, opposed jaws for clamping tissue therebetween, a clamping trigger, a resilient spring element fixed to the trigger, an actuator which translates movement from the clamping trigger to the movable jaws for clamping tissue, and an engaging element which is biased by the spring element against the actuator. When routine forces are applied by the user as the clamping trigger is moved to clamp tissue between the jaws, the engaging element causes the actuator to move in a forward direction for corresponding movement of the jaws from an open to a closed position. If excessive loads are applied, then the resilient spring element is compressed, and the engaging element is correspondingly released from its engagement with the actuator. Accordingly, further movement of the clamping trigger will not cause further translation of the actuator in the forward direction. Therefore, excessive loads are prevented, and the component parts of the instrument will be prevented from breaking. The invention is also applicable to actuators used for other functions such as stapling and cutting tissue.