Many of the unusual properties of the dwarf planet Pluto's orbit are
widely accepted as evidence for the orbital migration of the giant
planets in early solar system history. However, some properties remain
an enigma. Pluto's long term orbital stability is supported by two
special properties of its orbit that limit the location of its
perihelion in azimuth and in latitude. We revisit Pluto's orbital
dynamics with a view to elucidating the individual and collective
gravitational effects of the giant planets on its perihelion location.
In this presentation we demonstrate with numerical experiments that,
while the resonant perturbations from Neptune account for the azimuthal
constraint on Pluto's perihelion location, the long term and steady
persistence of the latitudinal constraint is possible only in a narrow
range of additional secular forcing which arises fortuitously from the
particular orbital architecture of the other giant planets. Our
numerical investigations also find that Jupiter has a largely
stabilizing influence whereas Uranus has a largely destabilizing
influence on Pluto's orbit.