The key theme behind Trump's epic acceptance speech was that he was going to fight for and protect all Americans from whatever it is that's throwing their world outta whack.
The media are incredulous, wondering why Trump is bothering to go after the black vote or the gay vote.
Unlike most politicians, however, he didn't address the various groups directly and try to win over their vote, as though it were a quid pro quo. He didn't put on a show about how "I feel your pain" to blacks who are out of the labor force because massive immigration has competed them out of the job market. Or to the gays, "I know how devastated you all must feel, but vote for me, and I'll protect you from Islamic terrorists who would attack your dance clubs."
Instead he spoke about them in the third person, as though his target audience didn't include many blacks or gays. Well, of course it doesn't -- gays make up only 1% of the electorate, and blacks have been members of the Democrat coalition since the 1960s.
Who is he really addressing, then? It's heterosexual people who put "concern for the gays" somewhere on their list of Really Important Political Goals. They are the ones who launched the gay marriage movement, who supported it among the electorate, and who are OK with it passing in the courts. The 1-2% of the population that's gay is not powerful enough to have done that all on their own, let alone in the span of one decade.
Likewise, when he talks about black unemployment and turmoil in black cities, he's addressing white people who put "concern for the blacks" on their list. If only blacks themselves were behind Black Lives Matter, there wouldn't be the kind of growing lawlessness that we're seeing. It's the white Minnesotans who are importing Somalis by the boatload out of "concern for the Africans". And it was their white Governor who came out and whipped the blacks up into a fury about how Philando Castile was shot by a racist cop (who was Mexican anyway).
If blacks were the primary demographic source of turning a state Democrat, then the South would still be Democrat. Those states have the highest percentages of blacks, all of whom vote Democrat, yet Southern states are solid Republican. And New England is deep blue, despite not having any blacks around to cast votes for Democrats. That difference is between white Southerners and white Yankees.
Aside from New England, the reliably blue states are those with intermediate levels of non-whites, where they're not like a second population (as in the Deep South, where they might be 20-40%), but where there's enough of them and in a confined area like a certain spot in a certain city (unlike the South where they range all over the geography). This makes the non-white population more like a pet zoo that the whites take care of.
Where there are no blacks, they're out of sight and out of mind. Where there are 40% blacks, why worry about them when there's enough of them to make up their own second society? But when there's 15% blacks, and they all live in five neighborhoods across only three cities, then whites adopt the mindset of "black community management," and are concerned for how government policies will help to manage black communities.
These are states like Illinois, Ohio, Michigan, Wisconsin, New York, Pennsylvania, Colorado (with Hispanics), and so on. They are blue not because their black populations are so large (they're not), but because a big chunk of white voters in the state are concerned about the welfare of blacks and are voting on behalf of blacks, or as "allies of blacks" -- not necessarily as a single-issue thing, but as part of their broader list of liberal concerns.
This assessment is supported by recent data on the 2012 election, which shows that voters were a lot whiter than the experts had thought. It's white liberals who make so many states blue, not the non-white population.
That's even more stark for gay voters, who couldn't swing the vote in any state. It's straight people who are either pro-gay marriage or anti, that determines whether a state is red or blue.
Trump is therefore trying to peel off white liberals who are concerned about the welfare of blacks and gays, as part of his broader campaign to undo or sidestep identity politics. Black voters want someone who will feel their pain, be their symbolic presence in office, and so on. Trump is not offering that, so he won't be winning over much of them.
But white liberals aren't black themselves, and think of "the welfare of blacks" in more material and utilitarian terms, rather than symbolic, identity, and emotional terms. White liberals are at least open to the argument that importing massive numbers of immigrants, on top of the tens of millions who are already here, is bad for blacks because of lower-skilled labor market competition.
In material terms, competition from immigrants pushes black citizens further into poverty, and drives them out of entire cities when they can no longer afford rent, after losing out in the labor market.
That's not to mention the ethnic conflicts that erupt between Mexicans and blacks, with Mexican gangs ethnically cleansing the black hold-outs in formerly all-black neighborhoods out West.
The same goes for gays. Trump is not offering them feel-good identity politics, a la "We accept your way of life and want you to feel welcomed". He's offering them protection from gay-targeted violence, which will appeal to white liberals who view "what's good for the gays" as physical well-being rather than emotional stuff.
Certainly some white liberals share the symbolic and emotional view that blacks and gays themselves have. But there's a decent chunk of white liberals for whom "concern for _____" is a utilitarian matter.
Re-framing "concern for blacks" in material rather than symbolic terms will take a long time, because it's a paradigm shift away from identity politics. But that's what it meant back in the New Deal and Great Society eras, and the re-alignment under way now is a rejection of identity politics in favor of material concerns.
Peeling off white liberals will be harder than tapping into disaffected voters, since liberals tend to already affiliate so much with Democrats. Still, Trump only needs a decent enough share of them, in a certain number of states, to go over the top.
Re-framing "concern for blacks, etc." as a dispassionate concern to protect all groups of Americans, with whom the leader does not necessarily identify, let alone pander to, could convince enough white liberals to vote Trump when the alternative is the cynical panderer who will import hordes of immigrants who will impoverish blacks further and make gays the target of Islamic terrorists.