Here is a useful graphic from the New York Times. You have to scroll to see the whole picture.
In words, and with some added remarks by yours truly:
- The US has about 324 million residents.
- 103 million are children, non-citizens, or disenfranchised felons. 324 – 103 = 221 million.
- 88 million people don’t vote. 221 – 88 = 133 million.
About 133 million people voted in the most recent presidential election.
- 73 million did not vote in this year’s primaries, but likely will vote in the general election. 133 – 73 = 60 million.
- About 31 million voted in this year’s Democratic primaries and 29 million in this year’s Republican ones.
- Hillary Clinton won this year’s Democratic primary with about 17 million votes to Sanders’s 14 million.
The Democrats assigned delegates proportionally. (If the Democrats had used Republican rules, she would have won the delegate race overwhelmingly.) This also shows that the super-delegates had nothing to do with her victory, which she won fair and square with a majority of primary voters.
Trump won the Republican primary having received about 13 million votes, with 16 million other votes going to his opponents. That is, not only did Trump not win a majority, he had fewer votes than either of the Democratic candidates.
Furthermore, after the first primaries, the Republican primaries were winner take all or winner take most. Trump would win all the delegates with 40% of the vote, for example. Thus the primaries were rigged in his favor. The Republican party, of course, didn’t do this on purpose to benefit him when they set up the rules after the presidential election 4 years ago. (If the Republicans had used the Democratic rules, there would have been a contested convention, as Trump would not have had a majority of the delegates.)
Now, most Republicans are not racists and bigots, but some are (and so are some Democrats, some Libertarians, and so forth). The Republican party has long worked for bigots to feel at home in the party. It does this with code words and dog whistles, but Donald Trump, himself a racist, doesn’t bother to use the code words and dog whistles. This is what he means when he says he is not politically correct.
The racists and bigots among Republicans are unhappy that their views have become unsuitable for polite society. They don’t think that they are racists and bigots. They think that they are sensible good people. They love that Donald Trump expresses what they believe to be the truth about Muslims, Mexicans, and blacks. This explains their passion for him.
As the graphic shows, choosing which candidate will represent a party in a national election is done by a small fraction of each party and of the general electorate. Small differences in turnout can make the difference between victory and defeat. Trump has successfully drawn the racists and bigots among Republicans to him and away from the others. But his supporters are not only the racists and bigots. Hence his victory, with about 9% of the general electorate voting for him in the primary and about 13 million of 60 million Republicans, about 20% of all Republicans.
Well, to draw those people to him, he had to alienate plenty of other people, both Republicans and Democrats. We can hope that the alienated ones will be sufficient to defeat him.