One word shows how much we've changed the way we talk about race

But if you really want to know how far standards for racially offensive speech have changed in America, you only need to start with one word:

Macaca.

George Allen was a popular Republican US senator cruising to a re-election victory in Virginia in the summer of 2006 when he used the word at a campaign rally to describe an Indian-American man holding a camera in the virtually all-white crowd.

"So welcome, let's give a welcome to Macaca here. Welcome to America, and the real world of Virginia," Allen said.

Macaca is a derogatory term meaning filthy monkey that some white colonists in Africa had used to describe African natives. Allen later apologized, saying he didn't know it was a racial slur. But he was criticized so heavily by both Republicans and Democrats that he lost his re-election bid, and his political career -- which some said was destined for the Oval Office -- never recovered.

"There are very few people left in either party who want to nominate somebody who has a history of racial insensitivity," political analyst Larry Sabato said at the time.

If a politician used Macaca today, would his or her career be finished?

That question is debatable because the standards for racially offensive language are shifting, some historians say. Virtually every week a tape of some person spewing racially offensive language in public goes viral. Racist language and imagery dot social media.

Critics say President Donald Trump has given people permission to be openly racist. Consider these comments from the President: Some Mexican immigrants are "rapists." Democrats want illegal immigrants to "infest" America. Haitians and Africans come from "s---hole" countries. And some "very fine people" marched alongside white supremacists last summer in Charlottesville, Virginia.

Trump rose to political prominence on a racist "birther" conspiracy theory. He repeatedly suggested that the nation's first black President was an Oval Office fraud born in Kenya. The New York Times recently published a "definitive list" of racially insensitive remarks by Trump stretching back to the 1970s.

Jeremy Levitt, a professor at Florida A&M University College of Law who has written about Trump, says the President is a "fire-starter," someone who "accentuates our inner-worst biases."

"He's a racial arsonist," Levitt says.

When "Roseanne" was canceled after Barr's racist tweet, Valerie Jarrett -- the former Obama adviser who was the comedian's target -- said Trump was partly responsible because "the tone does start at the top." The White House didn't respond to requests for comment.

An unspoken deal

This constant barrage of racially offensive language causes standards to shift, says Jacob Levy, author of an essay titled "The Weight of the Words."

"Things begin to seem normal when they weren't normal before. Now you have a large population with more tolerance for racism than would have been publicly acceptable 10 years ago," says Levy, who is also a political scientist at McGill University in Canada.

It used to be different. Few people knew what Macaca meant when Allen used it in 2006, but it didn't matter. There was zero tolerance for any remark that was seen as racist.

Former NFL sportscaster Jimmy Snyder, known as "Jimmy the Greek," lost his job when he said that blacks were superior athletes because of breeding from slavery. And Trent Lott resigned as Senate majority leader in 2002 after he seemed to suggest that the United States could have avoided "all these problems" if it had remained segregated.

Using racially offensive talk seemed like a vulgar relic of a shameful era, Levy says.

In "The Weight of the Words" essay, he wrote:

"The norm against publicly legitimizing Klan-type explicit racism was built up over a long time, calling on white Americans to be better than they were, partly by convincing them that they were better."

Somewhere in the late 1960s, most American politicians made an unspoken deal with the public. Dog-whistle phrases, or coded racial appeals, were fine: states' rights, forced busing and law and order. But raw racist rhetoric was no longer acceptable.

People may quibble over when this deal was made. Some point to one person and one year:

George Wallace and 1968.

Wallace was a proud white supremacist whose favorite speechwriter was a former Klansman. The former governor of Alabama once vowed in his inaugural speech, "Segregation forever!" He won five Southern states and about 10 million votes when he ran as a third-party candidate for the presidency in 1968.

But by the time Wallace ran for president, the rules of racial rhetoric had already begun to change. The Rev. Martin Luther King Jr. was assassinated that same year. Race riots were spreading across America. And two monumental civil rights laws -- the Civil Rights Act of 1964 and the 1965 Voting Rights Act -- were already reshaping American society.

Even Wallace, who used the N-word to appeal to Alabama voters, abandoned raw racial language during his presidential run, historians say. He later apologized for his racially insensitive remarks.

Trump's string of racially offensive remarks, though, unraveled that deal, Levy says: "There's so much desensitization to what Trump says that you can't stay shocked every day."

There are already hints that the United States is becoming more intolerant.

A new report says that anti-Semitic incidents in the country had their largest single-year increase on record in 2017. Trump's rhetoric and policies are driving a spike in hate crimes against Muslim and South Asian communities, another report says. And the Anti-Defamation League said that white supremacist groups are now hanging banners from freeway overpasses with slogan such as "WHITE FAMILIES MATTER," "'DIVERSITY' IS A CODE WORD FOR GENOCIDE" and "UNjew HUMANITY." Steve Bannon, Trump's former White House chief strategist, recently told a far-right gathering in France: "Let them call you racists. ... Wear it as a badge of honor."

There are those, however, who deny the notion that Trump has established a trickle-down racism that emboldens ordinary people to use and accept racist remarks in public.

Instead, many support Trump because his language allows them to be comfortable being white, says Ian Haney López, a law professor at the University of California, Berkeley, and author of "Dog Whistle Politics: How Coded Racial Appeals Have Reinvented Racism and Wrecked the Middle Class."

"He understands that his base sees whites as victimized, and (they) believe one of the primary ways that they are victimized is by being falsely accused of being racist," Haney López says. "Trump says things that border on being racist, and almost dares pundits to label them racist. And then Trump goes to his base and says, 'They're accusing you of being a racist.' "

If anything, Trump's language liberates people who felt constrained by political correctness, says Musa Al-Gharbi, a sociologist at Columbia University and author of an essay in The American Conservative magazine, "Social Science Fails to Prove Racists Elected Trump."

"He's weakened the stigma of being branded a racist," he says. "People feel like they can express themselves much more forcefully when it comes to immigration, crime or inequality. But this is not the same thing as actually becoming more racist."

A looming danger

Words matter. Language that dehumanizes another group can lead to all sorts of atrocities -- particularly when they come from people in positions of power, author Maria Konnikova wrote in a 2017 New Yorker essay on "How Norms Change."

Konnikova challenged a common assumption about the 1994 genocide in Rwanda, when Hutu tribe members murdered at least 800,000 of their Tutsi neighbors in a three-month period.

Many people think the violence occurred simply because there was so much ethnic tension between the groups. But both had long held stereotypical views of one another without the scale of violence that occurred, Konnikova wrote.

What triggered the violence were the messages that came from people in positions of power and respect in Rwanda, she says. Hutu leaders took to the radio calling Tutsis "cockroaches." Konnikova wrote that "norms can shift at the speed of social life" when the wrong leaders command the public megaphone.

"To a great extent, the norms in Rwanda shifted so rapidly because they did so from the top: Influential radio stations broadcast a powerful, persuasive and constantly repeating message urging listeners to join killing squads and organize roadblocks," Konnikova wrote.

No one is saying Americans are poised to go after one another with machetes and commit genocide. But Americans don't have to look at Rwanda to see how dehumanizing language could make atrocities possible, says Jennifer Mercieca, a Texas A&M University speech professor and author of the essay "The Rhetorical Brilliance of Trump the Demagogue."

"If you look back in American history, one of the ways that Americans could convince themselves that it was OK to possess people as property is through calling them objects," Mercieca says.

Norms are fragile in a country like the US -- a multiethnic democracy where one group that subjugated another is poised to become the minority in the future, says Steven Levitsky, co-author of "How Democracies Die."

There is no country in history that has managed to be both multiethnic and genuinely democratic, he said.

"I can't come up with a single example of a multiracial society in which there was a reasonable level of racial equality and everyone shared the same rights and democracy was sustained," Levitsky says.

In his book, Levitsky talks about a concept known as "defining deviancy down." It's why some say it's dangerous when a society starts accepting offensive language it rejected before.

"When unwritten rules are violated over and over, we become overwhelmed -- and then desensitized," Levitsky wrote. "We grow accustomed to what we previously thought to be scandalous."