gop caters - at least in terms of lip service - to veterans, landowners/homeowners, small business operators, rural people
they're aware that they're not rich, and the myth of temporarily embarrassed millionaires is overstated; they do, however, see something to lose with respect to at least the caricature of urban democratic policy
veterans - according to ones i've spoken with on political matters - consider the gop more generous with respect to benefits
homeowners/landowners see their ability to pay mortgage compromised by tax hikes - though to be fair, gop elimination of tax credits screw them too
small business operators are threatened by increases in corporate taxes - which affect far more than just large corporations - and complexities/tediousness of regulatory compliance
rural republicans like to do what they like, and see democrats as inclined to police what they can do with their property
and of course you've got the evangelicals, but that's an entire discussion in itself