Were there alternative grand policy domains that ought to have been inserted into this analysis along the way? Our reading of postwar political history was that the four domains ultimately selected were in fact the major recurrent realms for policy conflict; we think the voting analysis vindicates that judgment. Yet, in pursuit of the internal structure of four great policy domains on the way to creation of the basic voting model, it was intermittently necessary to remove an item that did not belong to any of these four but that did have policy implications. In effect, these items constitute the hunting ground for any additional domain. They thus raise the analytic questions appropriate to an afterword. Can any number of these items, too, be formed into coherent policy dimensions? If so, do any of these dimensions have sufficient impact on the presidential vote to justify inclusion in the voting model?

The most theoretically promising of these putative alternative domains is probably environmentalism; that is, governmental intervention to protect or enhance the natural environment (Hays 1987; Dunlap 1991; Dunlap and Scarce 1991). This is a keystone element in what is sometimes treated as an even larger alternative realm under the heading of “postmaterialism” (Inglehart 1977, 1990). Regardless, its substantive core remains sufficient to distinguish items that belong centrally to the putative domain, that do not belong to it at all, or that blend environmentalism with some other realm.