A surgical instrument, comprising: a shaft; an end effector extending from said shaft, said end effector comprising a staple cartridge, wherein said staple cartridge comprises: a cartridge body; staples removably stored in said cartridge body; and a sled configured to eject said staples from said cartridge body during a staple firing stroke; and a firing assembly within said shaft, said firing assembly being configured to apply a firing force to said sled during said staple firing stroke, wherein said firing force is a pushing force, wherein said firing assembly comprises: a first firing rod; a second firing rod, wherein said second firing rod is displaceable relative to said first firing rod; and a pushing force lockout system at least partially positioned intermediate said first firing rod and said second firing rod, wherein said pushing force lockout system is configured to engage said shaft and stop said staple firing stroke if said firing force exceeds a threshold; the surgical instrument further comprising a biasing member positioned intermediate said first firing rod and said second firing rod, wherein said biasing member is configured to apply a biasing force to said first firing rod which opposes said firing force, wherein said firing force can be transmitted from said first firing rod to said second firing rod through said biasing member the pushing force lockout system further comprising: a lock mounted to said shaft, wherein said lock is displaceable between an unlocked position and a locked position, and wherein said lock is configured to engage said second firing rod and prevent said firing assembly from performing said staple firing stroke when said lock is in said locked position; and a spring configured to bias said lock into said locked position; and an actuator rotatably mounted to said first firing rod, wherein said second firing rod is configured to rotate said actuator away from said lock when compression of the biasing member exceeds a threshold compression due to said firing force exceeding said threshold, such that said spring displaces said lock into said locked position. a shaft; an end effector extending from said shaft, said end effector comprising a staple cartridge, wherein said staple cartridge comprises: a cartridge body; staples removably stored in said cartridge body; and a sled configured to eject said staples from said cartridge body during a staple firing stroke; and a cartridge body; staples removably stored in said cartridge body; and a sled configured to eject said staples from said cartridge body during a staple firing stroke; and a firing assembly within said shaft, said firing assembly being configured to apply a firing force to said sled during said staple firing stroke, wherein said firing force is a pushing force, wherein said firing assembly comprises: a first firing rod; a second firing rod, wherein said second firing rod is displaceable relative to said first firing rod; and a pushing force lockout system at least partially positioned intermediate said first firing rod and said second firing rod, wherein said pushing force lockout system is configured to engage said shaft and stop said staple firing stroke if said firing force exceeds a threshold; a first firing rod; a second firing rod, wherein said second firing rod is displaceable relative to said first firing rod; and a pushing force lockout system at least partially positioned intermediate said first firing rod and said second firing rod, wherein said pushing force lockout system is configured to engage said shaft and stop said staple firing stroke if said firing force exceeds a threshold; the surgical instrument further comprising a biasing member positioned intermediate said first firing rod and said second firing rod, wherein said biasing member is configured to apply a biasing force to said first firing rod which opposes said firing force, wherein said firing force can be transmitted from said first firing rod to said second firing rod through said biasing member the pushing force lockout system further comprising: a lock mounted to said shaft, wherein said lock is displaceable between an unlocked position and a locked position, and wherein said lock is configured to engage said second firing rod and prevent said firing assembly from performing said staple firing stroke when said lock is in said locked position; and a spring configured to bias said lock into said locked position; and an actuator rotatably mounted to said first firing rod, wherein said second firing rod is configured to rotate said actuator away from said lock when compression of the biasing member exceeds a threshold compression due to said firing force exceeding said threshold, such that said spring displaces said lock into said locked position. a lock mounted to said shaft, wherein said lock is displaceable between an unlocked position and a locked position, and wherein said lock is configured to engage said second firing rod and prevent said firing assembly from performing said staple firing stroke when said lock is in said locked position; and a spring configured to bias said lock into said locked position; and an actuator rotatably mounted to said first firing rod, wherein said second firing rod is configured to rotate said actuator away from said lock when compression of the biasing member exceeds a threshold compression due to said firing force exceeding said threshold, such that said spring displaces said lock into said locked position.