  We argue that spin alignment of the vector mesons observed in unpolarized
hadron-hadron collisions is closely related to the single spin left-right
asymmetry observed in transversely polarized hadron-hadron collisions. We
present the numerical results obtained from the type of spin-correlation
imposed by the existence of the single-spin left-right asymmetries. We compare
the results with the available data and make predictions for future
experiments.
