An apparatus for operating on tissue, the apparatus comprising: (a) a body assembly; (b) a shaft extending distally from the body assembly, wherein the shaft defines a longitudinal axis; (c) an acoustic waveguide, wherein the waveguide comprises a flexible portion; (d) an articulation section (210, 310, 410) coupled with the shaft, wherein a portion of the articulation section encompasses the flexible portion of the waveguide, wherein the articulation section further comprises: (i) a first member (220, 320, 420), and (ii) a second member (202, 302, 402), wherein the second member is longitudinally translatable relative to the first member; (e) an end effector comprising: (i) an ultrasonic blade (242, 342, 432) in acoustic communication with the waveguide, and (ii) a clamp arm (244, 344, 444), wherein the clamp arm is coupled with the first member and the second member; and (f) an articulation drive assembly operable to drive articulation of the articulation section to thereby deflect the end effector from the longitudinal axis, wherein the articulation drive assembly comprises a pair of translating members (212, 214, 312, 314, 412, 414), wherein the translating members are operable to translate simultaneously in opposite directions to thereby deflect the end effector from the longitudinal axis, wherein the translating members are further operable to translate simultaneously in the same direction to thereby drive the clamp arm toward and away from the ultrasonic blade. (a) a body assembly; (b) a shaft extending distally from the body assembly, wherein the shaft defines a longitudinal axis; (c) an acoustic waveguide, wherein the waveguide comprises a flexible portion; (d) an articulation section (210, 310, 410) coupled with the shaft, wherein a portion of the articulation section encompasses the flexible portion of the waveguide, wherein the articulation section further comprises: (i) a first member (220, 320, 420), and (ii) a second member (202, 302, 402), wherein the second member is longitudinally translatable relative to the first member; (i) a first member (220, 320, 420), and (ii) a second member (202, 302, 402), wherein the second member is longitudinally translatable relative to the first member; (e) an end effector comprising: (i) an ultrasonic blade (242, 342, 432) in acoustic communication with the waveguide, and (ii) a clamp arm (244, 344, 444), wherein the clamp arm is coupled with the first member and the second member; and (i) an ultrasonic blade (242, 342, 432) in acoustic communication with the waveguide, and (ii) a clamp arm (244, 344, 444), wherein the clamp arm is coupled with the first member and the second member; and (f) an articulation drive assembly operable to drive articulation of the articulation section to thereby deflect the end effector from the longitudinal axis, wherein the articulation drive assembly comprises a pair of translating members (212, 214, 312, 314, 412, 414), wherein the translating members are operable to translate simultaneously in opposite directions to thereby deflect the end effector from the longitudinal axis, wherein the translating members are further operable to translate simultaneously in the same direction to thereby drive the clamp arm toward and away from the ultrasonic blade.