  Interlayer tunneling measurements in the strongly correlated bilayer
quantized Hall phase at $\nu_T=1$ are reported. The maximum, or critical
current for tunneling at $\nu_T=1$, is shown to be a well-defined global
property of the coherent phase, insensitive to extrinsic circuit effects and
the precise configuration used to measure it, but also exhibiting a surprising
scaling behavior with temperature. Comparisons between the experimentally
observed tunneling characteristics and a recent theory are favorable at high
temperatures, but not at low temperatures where the tunneling closely resembles
the dc Josephson effect. The zero-bias tunneling resistance becomes extremely
small at low temperatures, vastly less than that observed at zero magnetic
field, but nonetheless remains finite. The temperature dependence of this
tunneling resistance is similar to that of the ordinary in-plane resistivity of
the quantum Hall phase.
