  We renormalize the two-nucleon interaction at leading order (LO) in chiral
perturbation theory using the scheme proposed by Nogga, Timmermans, and van
Kolck--also known as modified Weinberg counting. With this interaction, we
calculate the energy per nucleon of symmetric nuclear matter in the Brueckner
pair approximation and obtain a converged, cutoff-independent result that shows
saturation, but also substantial underbinding. We find that the renormalized LO
interaction is characterized by an extraordinarily strong tensor force (from
one-pion exchange), which is the major cause for the lack of binding. The huge
tensor force also leads to the unusually large wound integral of 40% in nuclear
matter, which implies a very slow convergence of the hole-line or
coupled-cluster expansion, rendering this interaction impractical for many-body
calculations. In view of the unusual properties of the renormalized LO
interaction and in view of the poor convergence of the nuclear many-body
problem with this interaction, there is doubt if this interaction and its
predictions can serve as a reasonable and efficient starting point that is
improved by perturbative corrections.
