Few things. The "Southern Strategy" may have been partially derived from segretagationist policies, but so was everything else. It's a cumulation of responses to forces both inside and outside their control; it was a giant back lash completed by many demographics, including those not inside the original groups designing old Anglo-Saxon conformist policies, responding to what was perceived as movements contradicting accepted and comfortable norms. [Strong feminism, "Hippie-ism," Black militantinism / “socialist” proposals, 1970's economic depression, pretty much everything] They were Catholics, Jews, Women, some Blacks, all participated in the revival of the Reagan era. The point is that it was influenced by many things and would have been created even had it had its origins from elsewhere. Denouncing the Southern Strategy on its origins, if that is anyone's intention, and then claiming its revival is its origin in disguise is meritless and essentially one giant crazy man's ad hominon argument. It shows a complete lack of understanding of recent American history in general.
The Religious Right Movement tapped into those who were religious and felt those other movements were pushing too far against what people at the time were comfortable with. In kind, the religious voted republican, Reagan, and Bush and accepted republican platforms like neoconservative economic platforms. Afterall, it's a two party system.
The dependency and future viability of the religious right movement, I imagine, will depend on a whole mess of factors. First, whether the religious in particular are going to be uncomfortable against perceived demands of other movements; whether those movements seem impartial and would respect the religious. Also whether the alleged new religious right will be just as offended as the ones back in the 1980s. We can't predict the future, but I'm imagine the demand of the religious right is going to die down as concerns for more earthly matters become more pressing. [but seeing how so many people have been trained to believe one particular economic system is better than the other, I don’t see republican or democratic parties dwindling short of demographic increase] The sixties and seventies were unique times, I don’t think they can be replicated but humans are always fickle and I imagine the religious right re-surfacing once the economy improves and/or once other groups take the opportunity to create law and society against what the majority population is comfortable with. And even then, it’s no guarantee it’ll be just as powerful, less powerful, or more powerful. Who knows. Even more so, we’re still not sure the religious right movement is even gone. They lost one presidential election; wait until the next election and then see how large of an influence they still have.
I'd also to point out that the Pope or whoever's in charge doesn't speak for all American Catholics. It's actually kind of laughable. The lot of us are Closet Protestants since there it’s difficult to claim to be from an particular European ethnicity and still claim to be protestant, and most simply vote on how they are inclined personally regardless of what some old White European in the Vatican says. (no offense to Europeans)
Edit: Dispite Formaldehyde's one sided rheotoric; he is right about the Soviet Union. During the period of the Cold War, success was typically proven by industrialization and western concepts of progress. Compared to the development of progress of the US and Europe, along with the progression of technology, the USSR wasn't able to keep up, relented, and decided to liberalize their markets to progress. The old model was failing. Reagan merely pushes spending to compel the USSR to push even harder making them fall sooner. There are other reasons, of course. Most, if not all, of the aggressive tactics in the 1980s was done by the US where the USSR was taking care of its own problems by the 1980s. However, saying Truman's decision to drop the two A-bombs on the Japanese was a warning is speculation at best. That might have been the reason, it might have been a reason. But there's no smoking letter saying "I'm Truman. I dropped two A-bombs tonight because I simply wanted to scare the Russians." Don't ignore all the other explanations just because it supports your skewed bias. thx.