  Using a phenomenological lattice model of coupled spin and charge modes, we
determine the spin susceptibility in the presence of fluctuating stripe charge
order. We assume the charge fluctuations to be slow compared to those of the
spins, and combine Monte Carlo simulations for the charge order parameter with
exact diagonalization of the spin sector. Our calculations unify the spin
dynamics of both static and fluctuating stripe phases and support the notion of
a universal spin excitation spectrum in doped cuprate superconductors.
