Many different factors, I think, and people answering this question can debate them forever without agreeing with each other.
For me, though, I can think of at least 3 reasons why American racism has been so persistent. If you want to add other reasons, you may be right - or maybe not. But here are my 3 reasons:
1. Racism, especially white racism against black people, has a really long history in this society, dating back to the slave trade and the slave-based plantation economy of the South before the Civil War, and extending forward through the infamous "Jim Crow" era of legal segregation and Klan terrorism in the South to at least the 1960s.
Actually, black slavery in the Western Hemisphere existed well before the America Revolution and the founding of the US - since black slave labor was essential to the sugar cane plantations that were key to Spanish, Portuguese, French and British colonies relatively soon after Columbus's "discovery" of the Americas.
That history of racial discrimination, the importance of race-based slavery to the economies of many New World societies from the 1500s onward, and the cultural justifications for slavery that the white plantation owners and slave traders dreamed up have left very deep marks on US society.
They've been internalized psychologically by millions of people, they've become traditional in some families, and they've led to a bad karma of racial conflicts between different groups of Americans, a bad karma that often perpetuates itself. We can't get rid of those marks overnight.
2. In some ways, it can be argued that elements within our language and our religious and philosophical imagery in the West, dating back to the Babylonian captivity of the Jews in ancient Persia, are inherently racist in the sense of being anti-black.
The ancient Zoroastrians, far more than the Jews before the Babylonian Captivity, thought of the universe as being a battleground between a "good" supreme being -- Ahura Mazda, lord of light -- and a "bad" supreme being, Ahriman, who basically was the lord of darkness.
This white-vs-black imagery crept into Judaism during the 70 years the Jewish people spent under Persian captivity and, through Judaism, went on to influence Christianity.
We can still see elements of this "white is good" and "black is bad" imagery in the English language today.
A "black" mood or a "black" despair is a very bad one; a "black day" is often a day of disaster, like Black Friday in October 1929 when the Wall Street stock market collapsed, bringing on the Great Depression.
"Black" comedy is angry or negative in tone; "light" comedy is funnier and happier; a "black" cat is supposedly a sign of bad luck, etc. etc. etc.
Obviously everyone with a brain knows, on a conscious level, that suffering from "black" despair or a "black" mood or having a "black day" is not literally connected with being African American.
Having a "black mark" on your record or being a "black-hearted villain" really has nothing to do with race -- we realize with our conscious minds.
But words and images are powerful things, and I suspect that they work on the subconscious minds of millions of Americans -- of all races -- in ways that cause most of us to be more racist than we consciously mean to be.
3. A third likely factor in American racism -- unlike the racism in other countries, which may have different causes -- is status anxiety.
Far more than people in many other societies, Americans have a sense of social and economic mobility, and the myth is that we all can succeed and enter the "middle class" or even "marry a millionaire" if we're smart enough, hardworking enough, or lucky enough.
But some historians believe this makes many of us insecure about our socio-economic status, since our status is open to changing either for good or for bad.
And being insecure about status, no one wants to be stuck on the bottom of the so-called totem pole. No one wants to be the lowest-status, most despised person around.
According to a white historian named George Frederickson (I think is his name), this insecurity about status inspires many white people to look for someone to be even lower on the totem pole than we are. We don't want to have the lowest status; we want someone else to be below us.
And therefore many of us have an invest in looking down on "inferior" (supposedly) people of other races, so we don't have to be "it" in the game of tag. We insist that they are "it" instead.
4. Another factor in maintaining and in fact increasing American racism over the past 50 years has been the rise of "Dog Whistle Politics" and its use for political ends by rich Republicans, the members of the so-called 1 percent.
As Donald Trump's supporters are well aware, the GOP establishment hasn't done such a wonderful job of protecting the economic interests of middle class white people over the past half-century.
To get middle class white people to vote for Republican policies that often don't help the average person, but do help the rich and powerful, the politicians have perfected the art of appealing to buried white racism and white racial fears -- some of them conscious, some probably subconscious -- through coded signals, like high-pitched dog whistles that only dogs can hear.
Dog-whistle code words and images such as "war on crime," "war on drugs," "welfare queens," "welfare cheaters" etc etc. often succeed in persuading otherwise decent and sensible white voters to support Republican (and some Democrat) policies that are bad for unions, cruel to the poor and disabled, and in some cases, economically stupid - for instance, our nation's absurdly overgrown prison system.
"Dog whistle politics" that appeals to racial bias and racial fears obviously also helps to keep politicians using these hidden racist signals in office.
But one unfortunate side effect -- maybe intentional, maybe accidental on the politicians' part -- is to increase racial prejudice and racial conflict in the country.
Which is not really good for America on the world stage, when you think about it, and doesn't really make many of us safer at home.
- democratic socialist