  A simple model for the transmission of pairs of electrons through a weak
electric link in the form of a nanowire made of a material with strong electron
spin-orbit interaction (SOI) is presented, with emphasis on the effects of
Coulomb interactions and the Pauli exclusion principle. The constraints due to
the Pauli principle are shown to "quench" the coherent SOI-induced precession
of the spins when the spatial wave packets of the two electrons overlap
significantly. The quenching, which results from the projection of the pair's
spin states onto spin-up and spin-down states on the link, breaks up the
coherent propagation in the link into a sequence of coherent hops that add
incoherently. Applying the model to the transmission of Cooper pairs between
two superconductors, we find that in spite of Pauli quenching, the Josephson
current oscillates with the strength of the SOI, and may even change its sign.
Conditions for an experimental detection of these features are discussed.
