Since the mid–1990s, comparative research on welfare state evolution hascontrasted the contours of postwar social policy expansion with theparameters of contemporary programme retrenchment. Paul Pierson's 1994account of pension, housing and income support policies in the UnitedKingdom and the United States during the Thatcher and Reagan yearsproposed two core arguments with this literature: first, welfare stateexpansion and contraction were governed by fundamentally differentdynamics; and second, even conservative, ideologically committedpolitical executives found it hard to impose radical social policychanges. Because “the welfare state has proved to be far more resilientthan other key components of national political economies.”Pierson hasmaintained, “retrenchment is a distinctive and difficult politicalenterprise.”