  Evidence that the pseudogap (PG) in a near-optimally doped
Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ sample destroys the BCS logarithmic pairing
instability [1] raises again the question of the role of the PG in the
high-temperature superconducting cuprates [2]. The elimination of the BCS
instability is consistent with the view that the PG competes with
superconductivity. However, as noted in [1], the onset of superconductivity
with a $T_c \sim 90$ K suggests an alternative scenario in which the PG
reflects the formation of short range pairing correlations. Here, we report
results obtained from a dynamic cluster quantum Monte Carlo approximation (DCA)
for a 2D Hubbard model and conclude that (1) the PG, like the
superconductivity, arises due to short-range antiferromagnetic correlations and
(2) contrary to the usual case in which the pairing instability arises from the
Cooper instability, here, the strength of the spin-fluctuations increases as
the temperature decreases leading to the pairing instability.
