The political party environment post 1945 and into the 1970s and beyond has been likened by some to a semi-pillarization model with class and religion and the associated organizational and group structures forming the key mainstays of support for the main parties. The Conservatives received significant class based support from middle-class voters as well as bedrock of Protestant working-class voters often with strong connections to church membership. Labour's pillars of support were class based too with work based trade union networks, but this conflated with the very large numbers of Labour voters, especially in west and central Scotland, adhering to the Roman Catholic church and its social and communal structures this conflation of course makes it difficult to determine the most important vote determinant, class or religious faith. Despite earlier commitment by the party to Scottish home rule, final movement towards support for devolution was simply a response to a threat from the Scottish National Party.