  I compute the effect on the power spectrum of tracers of the large-scale
mass-density field (e.g., galaxies) of primordial non-Gaussianity of the form
Phi=phi+fNL (phi-<phi^2>)+gNL phi^3+..., where Phi is proportional to the
initial potential fluctuations and phi is a Gaussian field, using
beyond-linear-order perturbation theory. I find that the need to eliminate
large higher-order corrections necessitates the addition of a new term to the
bias model, proportional to phi, i.e., delta_g=b_delta delta+b_phi fNL phi+...,
with all the consequences this implies for clustering statistics, e.g.,
P_gg(k)=b_delta^2 P_deltadelta(k)+2 b_delta b_phi fNL P_phidelta(k)+b_phi^2
fNL^2 P_phiphi(k)+... . This result is consistent with calculations based on a
model for dark matter halo clustering, showing that the form is quite general,
not requiring assumptions about peaks, or the formation or existence of halos.
The halo model plays the same role it does in the usual bias picture, giving a
prediction for b_phi for galaxies known to sit in a certain type of halo.
Previous projections for future constraints based on this effect have been very
conservative -- there is enough volume at z<~2 to measure fNL to ~+-1, with
much more volume at higher z. As a prelude to the bias calculation, I point out
that the beyond-linear (in phi) corrections to the power spectrum of
mass-density perturbations are naively infinite, so it is dangerous to assume
they are negligible; however, the infinite part can be removed by a
renormalization of the fluctuation amplitude, with the residual k-dependent
corrections negligible for models allowed by current constraints.
