This paper looks at the competing theses of polarising convergence and poli
cy-related divergence in the study of socioeconomic segregation. Using data
from Oslo, Norway, it is shown that the level of segregation has remained
fairly stable, or has even declined, in spite of increasing income inequali
ty. This spatial stabilisation is causally related to a more flexible desig
n in city planning and policy. It is, however, not a development in accorda
nce with the welfare state approach proposed by Chris Hamnett and some othe
r scholars. Rather, we observe a 'perverse' effect where social democracy h
as been helped by opposition policies. In consequence, the paper suggests t
he use of models of action and the identification of 'closed' and 'open' pr
ocesses of change.