Yes, there was a groundshift in Catholic/fundamentalist relations after Roe v Wade. But anti Semitism and anti Catholicism and suspicion of African Americans are always there under the surface. Nothing ever really goes away.
The outlook of the John Birch society is reflected in much of what Ron Paul proposed and in a lot of the Tea Party platform, which in turn is influencing more mainstream Republican policies; the GOP ignores the Tea Party at its peril. On issues like immigration and the proper role of the UN (see the career and views of John Bolton, US ambassador to the UN under GW Bush) there is little difference between it and mainstream Republicans. The general 'Patriot' groups and the John Birch Society and the Tea Party have many areas of overlap both wrt positions on various economic issues (trade and globalisation) and in tone (mortal danger to the US posed by too much integration into the rest of the world politically and economically, too much federal power threatening state rights). The labels may change but the sentiment remains.
Nixon has a lot to answer for. He appealed to the sense of many voters that the world had spun out of wasp control and popularised and normalised kneejerk reactionism by calling it the sentiment of the silent majority, with the implication that silence was bred of fear and a sense of solid middle class decency in the face of long haired radicals -- he summoned forth people motivated by fear to vote for him.
Reagan in his turn pushed the envelope that little bit further with the 'welfare queens' and the Willie Horton elements of his election campaign against Dukakis, both crude appeals to pure racism. The Reagan presidency saw the last hurrah of the Cold War but the fear that was instilled in American society from WW2 onwards continues to find expression in the anti-European and anti-any-whiff-of socialism- let-alone communism element of political discourse. Even Newt Gingrich, during the Republican primaries, sought to discredit Romney by revealing that he gasp spoke French. He could have accused Romney of shirking his national duty to go to Vietnam (and could possible have made much more political capital) but interestingly chose to attack Romney on his alleged cultural affinity to Europe instead.
I think Republican voters remain basically motivated much more by various fears than Democrats.
I don't think you can say with any certitude at all that the higher up the income scale you go the less likely people are to attend church services of whatever kind. My own observations of churches in a strikingly 'liberal' and very well off suburban area in the US midwest contradict your assertion. There was one particular street that I recall that had at one end a Catholic church, further on an Episcopalian and further on again an unaffiliated Christian church, and on any given Sunday morning driving on that street was impossible because of the vast numbers of parked cars of congregants. The three Jewish temples spread over two neighbouring suburbs had large congregations and they also stopped traffic, but on Saturdays. All the parked cars for all the congregations tended to be newer models, oodles of SUVs, lots of expensive European brands. Churches of all kinds all over the US tend to be much more full than in Europe.
I don't know where you are getting your widely acknowledged facts about who is a member of the Democratic party, and you are forgetting about the huge amount of urban poverty. There are states that are predominantly rural that vote Democratic and some that are swing states. There are states that have a large urban population and also a large rural one like Illinois. Maybe Minnesota too..
'and hating those who support their main ideas is exactly what liberals would want them to do so as they'd lap up the split vote and win all their electoral campaigns.'
This is conspiracy theory talk.