A theorem of A. Edmonds
says that any nonzero degree map between closed surfaces is homotopic to a
composition of a pinch map and a branched covering. Here we consider the analogous
problem in dimension three. We prove that any nonzero degree map between
P2-irreducible Seifert fibered spaces of infinite π1 is homotopic to a composition of
“vertical pinches” and a fiber preserving branched covering, except for a few cases
which we describe completely. In particular, any such degree one map is homotopic to
a composition of vertical pinches.