  We study a one-dimensional electron liquid coupled by a weak spin-exchange
interaction to an antiferromagnetic spin-S ladder with n legs. A perturbative
renormalization group analysis in the semiclassical limit reveals the opening
of a spin gap, driven by the local magnetic correlations on the ladder. The
effect, which we argue is present for any gapful ladder or gapless ladder with
$nS\gg 1$, is enhanced by the repulsive interaction among the conduction
electrons but is insensitive to the sign of the spin exchange interaction with
the ladder. Possible implications for the striped phases of the cuprates are
discussed.
