  The time dependent tidal interaction of the Local Group Dwarf Spheroidal (dS)
Galaxies with the Milky Way (MW) can fundamentally affect their dynamical
properties. The model developed here extends earlier numerical descriptions of
dS-MW tidal interactions. We explore the dynamical evolution of dS systems in
circular or elliptical MW orbits in the framework of a parametric oscillator.
An analytic model is developed and compared with more general numerical
solutions and N-body simulation experiments.
