1). The approaching minority-majority:(Consider miscegenation as a real threat to the Republican Party, especially in the Deep South, as it will pose a threat to white identity politics -- pb).
3). The increase in educated votersEducated voters are the dream voters for any political party. They are more likely to make political contributions, vote in an election, and participate in vote-getting activities. When they face a weak argument by someone unlearned they are more likely to change the mind of the unlearned person than to change their opinions. They are less likely to fall for a specious slogan. --pb
5). The decreased religious participationEven should religion make a comeback, it is likely to be more rational, and more focused on ethical issues instead of upon cultural divides.
2). The rise of millennialsAdd to this -- they are entering the ages in which they start running for and winning major political offices. If Republicans aren't attracting millennial voters with older politicians, then guess how well they will do when the Republicans have few successful Millennial politicians. Millennial politicians will have themes honed to win the largest generation of politicians -- themselves. -- pb
4). The decline of married householdsR
Same-sex couples are very much on the increase, and Republicans have little to offer them except a memory of themselves resisting same-sex marriage so long as they could get away with it. Heterosexual marriage will become more common as economic conditions improve for non-elites, so this is at most a transitory effect. --pb