How important is the three-nucleon force?
By calculating the contribution of the $\pi-\pi$ three-body force to the three-nucleon binding energy in terms of the $\pi N$ amplitude using perturbation theory, we are able to determine the contribution of the different $\pi N$ partial waves to the three-nucleon force. The division of the $\pi N$ amplitude into a pole and nonpole gives a unique procedure for the determination of the $\pi NN$ form factor in the model. The total contribution of the three-body force to the binding energy of the triton is found to be very small.