  I develop a renormalization-group blocking framework for lattice QCD with
staggered fermions. Under plausible, and testable, assumptions, I then argue
that the fourth-root recipe used in numerical simulations is valid in the
continuum limit. The taste-symmetry violating terms, which give rise to
non-local effects in the fourth-root theory when the lattice spacing is
non-zero, vanish in the continuum limit. A key role is played by reweighted
theories that are local and renormalizable on the one hand, and that
approximate the fourth-root theory better and better as the continuum limit is
approached on the other hand.
