"This is CNN Tonight, I'm Don Lemon. The president of the United States is racist. A lot of us already knew that." The CNN anchor's ice-cold open to his newscast on Thursday night was stunning and yet 100 percent spot-on — and a sign that America has crossed a Rubicon of sorts in our tortured, centuries-long history of how this nation treats race and ethnicity, which is the defining debate in our ever-present schizophrenia over what this nation really stands for.

In the Donald Trump era's crack-addled hyperactive news cycle, it was a long time ago — a.k.a. Thursday — that the 45th president of the United States sat at his desk in the Oval Office and told some 50 lawmakers and aides that he didn't want a flood of immigrants from "shithole countries" in Africa, part of a longer rap in which he denigrated immigration from places where the people are black — Haiti, Africa — while talking up blond and blue-eyed arrivals from Norway. It's impossible to find the right word to express the inhumanity of Trump's open-for-all-to-see beliefs. Horrific? Morally unconscionable? None seems to express the full outrage. On the weekend when America honors what would have been the 89th birthday of our greatest advocate for human rights, Dr. Martin Luther King Jr., the nation is now led by a man who clearly judges people not by the content of their character but by the color of their skin.

The president of the United States is racist. But as Don Lemon stated with high-def clarity, a lot of us already knew that. When America went to the polls on Nov. 8, 2016, we already knew so much. We knew that the federal government slammed Trump and his dad — who'd been arrested in his younger days at a KKK rally — for not renting to blacks in the 1970s, that Trump said in the 1980s that he wanted Jews and not blacks counting his money, that he purchased a full-page New York Times ad calling for the death penalty for five young blacks later found to be completely innocent (for which he still won't apologize), that he re-ignited his political fortunes by insisting the first African American president couldn't be a real American, and then ran a campaign centered on a wall to keep out Mexican "rapists," a travel ban based on people's Muslim religion, and punctuated by trafficking in the worst stereotypes about "inner cities."

Knowing all that, 62,984,825 Americans — scattered in just the wrong combination of states — voted for that guy to become our president.

And isn't that the bigger problem here? Trump's outrageously racist remark quickly became an international incident, a huge blow to America's image in the world that has already been reeling since the unfortunate events of Nov. 8, 2016, and a rallying cry for the 60 to 65 percent of Americans who already disapproved of what the president is doing. But it also became a rallying cry, of sorts, for a lot of the 36 Percent of Always Trumpers, who heard the phrase "shithole countries" applied to people they also want to keep out of the United States based on their prejudices, and saw a leader who finally spoke for them, doing the dirty work they elected him to do.

That is the much bigger problem with Trump's awful words. He's hardly the first racist to occupy the White House — in the second half of American history, Woodrow Wilson stands out, with terrible consequences for policy — but he's the first racist president to yell his hate speech into our 21st century toxic echo chamber. Within minutes, a network of paid right-wing pundits arrived in our living rooms to say that while they themselves wouldn't have used those exact words, aren't Haiti and most of Africa, in essence, actually s-hole countries?

"This is how the forgotten men and women in America talk at the bar," said the Fox News savant Jesse Watters, suggesting that racism is as American as cherry pie and what's so terrible about a president who says that out loud. Maybe that explains why, so far, fewer than a half-dozen GOP members of the House, none of them in leadership, have strongly criticized Trump's words, with their speaker Paul Ryan dismissing them merely as "unhelpful," with the New York Times editorial board adding, "clearly wishing he could return to his daily schedule of enriching the wealthiest Americans."

Trump's words only emboldened those on the extreme right. That includes white nationalists like Mike Cernovich — "Go move to Haiti. Or Liberia. Oh, you won't? Why is that?" he asked on Twitter — as well as former KKK chieftain David Duke and the neo-Nazi Daily Stormer, which said the president's slur "indicates Trump is more or less on the same page as us with regards to race and immigration."

Maybe you've heard of "the Overton window" — the idea of shifting the window of what ideas or words are acceptable, or even mainstream, in American political discourse and thought. For two years, Trump has been steadily moving the window of language and policies based on racial prejudice, both overtly or implied, to the extreme right, and conservative media and the millions of Americans who watch them are hopping on the bandwagon. That brings real-world consequences that are even worse than a president's poisonous words.

When the president can talk about "shithole countries" in the Oval Office and gets away with it, he gives fresh encouragement — permission, really — to the perpetrators of the so many hate crimes across America, and especially to all the impressionable kids who now delight at chanting "Trump, Trump, Trump" at mostly black or Latino schools, scrawl swastikas in school bathrooms, or yell "go back to your country" to immigrant kids. The grim future of intolerance in America.

When the president spews racism from inside "the people's house," he is not just showing off his own ignorance, but driving U.S. policy on immigration issues that are literally life or death issues for hundreds of thousands of people — the 800,000 young "Dreamers" who've done everything America could ask of them but now live in fear of deportation to countries they barely know, the 200,000 Salvadorans and 60,000 Haitians who fled both natural disaster and the man-made disasters of murder and drugs, now stamped with "Return to Sender" by an America that no longer is a beacon.

When the president uses vulgarity to dismiss entire nationalities that don't look like him or his supporters, it is the embodiment of his first year of policies that are designed to harm black and brown people — whether it's expanding the GOP's war on voting rights, deciding to look the other way on segregation in public housing, or bringing back marijuana arrests that disproportionately target African Americans.

When the president signals that hate has a home at 1600 Pennsylvania Ave., he's also sending a message that it's open season for human rights abuses to all the ICE officers who've decided they can "take the gloves off" in the Trump era and bust into courtrooms and schools in their search for the undocumented, to the Border Patrol agents who detained the 10-year-old girl returning from surgery, and to all the police officers who now know that if they shoot an unarmed black man, Jeff Sessions and his Justice Department will have their back.

When the president struts his racism on the eve of the Martin Luther King Jr. holiday, it's a stark reminder that America is led by a man who is taking a crowbar to the arc of the moral universe and twisting it away from justice. That is the dangerous line that we've just crossed. When Trump says something outrageous like he did on Thursday, there's a tendency to proclaim that this is not us, that this is not America. The actual truth is more complicated.

The nation that authored a progressive Bill of Rights with freedoms that were radical for their time, that welcomed millions of political and economic refugees and that sacrificed so much to help defeat fascism in the 1940s is also the nation that replaced slavery with Jim Crow and then mass incarceration, that has historically excluded immigrants based on their race … and that elected Donald Trump in 2016.

The America so repulsed by a president's rant against "shithole countries" is the same America that talks just like Trump at the bar. The question for 2018 and beyond is, which America is going to prevail?