We describe a strategy for attacking the canonical nuclear structure proble
m-bound-state properties of a system of point nucleons interacting via a tw
o-body potential-which involves an expansion in the number of particles sca
ttering at high momenta, but is otherwise exact. The required self-consiste
nt solutions of the Bloch-Horowitz equation for effective interactions and
operators are obtained by an efficient Green's function method based on the
Lanczos algorithm. We carry out this program for the simplest nuclei, d an
d He-3, in order to explore the consequences of reformulating the shell mod
el as a controlled effective theory.