  We establish the Hamiltonian analysis and the canonical path integral for a
local formulation of vacuum energy sequestering. In particular, by considering
the state of the universe as a superposition of vacuum states corresponding to
different values of the cosmological and gravitational constants, the path
integral is extended to include integrations over the cosmological and
gravitational constants. The result is an extension of the Ng-van Dam form of
the path integral of unimodular gravity. It is argued to imply a relation
between the fraction of the most likely values of the gravitational and
cosmological constants and the average values of the energy density and
pressure of matter over spacetime. Finally, we construct and analyze a
BRST-exact formulation of the theory, which can be considered as a topological
field theory.
