A surgical instrument, comprising: an end effector assembly having first and second jaw members (110,120), at least one of the jaw members movable relative to the other between a spaced-apart position, a first approximated position defining a first gap distance therebetween, and a second approximated position defining a second gap distance therebetween, wherein the second gap distance is less than the first gap distance; a drive assembly coupled to one or both of the jaw members (110,120), wherein the drive assembly is selectively longitudinally translatable, upon pivoting of a movable handle about a pivot, between first, second and third positions to move the jaw members between the spaced apart position and the first and second approximated positions, respectively; a knife selectively movable relative to the end effector assembly between a retracted position, a first extended position in which the knife extends between the jaw members (110,120) a first distance, and a second extended position in which the knife extends between the jaw members a second distance, wherein the second distance is greater than the first distance; a trigger selectively actuatable between a un-actuated position, a first actuated position, and a second actuated position for moving the knife between the retracted position, the first extended position, and the second extended position; and at least one second control member operably coupled to the trigger, characterized in that the surgical instrument further comprises a first control member fixed to the drive assembly and moveable therewith, the first and second control members (150,160) being configured to engage one another to: prevent movement of the trigger from the un-actuated position when the jaw members (110,120) are disposed in the spaced-apart position, permit movement of the trigger from the un-actuated position to the first actuated position and prevent movement of the trigger beyond the first actuated position when the jaw members are disposed in the first approximated position, and permit movement of the trigger from the un-actuated position to the second actuated position and prevent movement of the trigger beyond the second actuated position when the jaw members are disposed in the second approximated position. an end effector assembly having first and second jaw members (110,120), at least one of the jaw members movable relative to the other between a spaced-apart position, a first approximated position defining a first gap distance therebetween, and a second approximated position defining a second gap distance therebetween, wherein the second gap distance is less than the first gap distance; a drive assembly coupled to one or both of the jaw members (110,120), wherein the drive assembly is selectively longitudinally translatable, upon pivoting of a movable handle about a pivot, between first, second and third positions to move the jaw members between the spaced apart position and the first and second approximated positions, respectively; a knife selectively movable relative to the end effector assembly between a retracted position, a first extended position in which the knife extends between the jaw members (110,120) a first distance, and a second extended position in which the knife extends between the jaw members a second distance, wherein the second distance is greater than the first distance; a trigger selectively actuatable between a un-actuated position, a first actuated position, and a second actuated position for moving the knife between the retracted position, the first extended position, and the second extended position; and at least one second control member operably coupled to the trigger, characterized in that the surgical instrument further comprises a first control member fixed to the drive assembly and moveable therewith, the first and second control members (150,160) being configured to engage one another to: prevent movement of the trigger from the un-actuated position when the jaw members (110,120) are disposed in the spaced-apart position, permit movement of the trigger from the un-actuated position to the first actuated position and prevent movement of the trigger beyond the first actuated position when the jaw members are disposed in the first approximated position, and permit movement of the trigger from the un-actuated position to the second actuated position and prevent movement of the trigger beyond the second actuated position when the jaw members are disposed in the second approximated position.