Everywhere I go, people tell me how concerned they are by the divisive rhetoric coming from my opponent in this election. I understand that concern, because it’s like nothing we’ve heard before from a major party nominee for president of the United States.

From the start, Donald Trump has built his campaign on prejudice and paranoia. He’s taking hate groups mainstream and helping a radical fringe take over the Republican party. And his disregard for the values that make our country great is profoundly dangerous.

Just this week, under the guise of “outreach” to African Americans, Trump has stood up in front of largely white audiences and described black communities in insulting and ignorant terms. “Right now, you walk down the street, you get shot.” Those are his words.

Trump doesn’t see the success of black leaders in every field, the vibrancy of black-owned businesses, or the strength of the black church. He doesn’t see the excellence of historically black colleges and universities or the pride of black parents watching their children thrive. And he certainly doesn’t have any solutions to take on the reality of systemic racism and create more opportunity for every American.

It takes a lot of nerve to ask people he’s ignored and mistreated for decades, “What do you have to lose?” Because the answer is everything.

Trump’s lack of knowledge, experience, and solutions would be bad enough — but what he’s doing here is more sinister: Trump is reinforcing harmful stereotypes and offering a dog whistle to his most hateful supporters. And it’s a disturbing preview of what kind of president he’d be.

I know some still want to give Trump the benefit of the doubt and hope there’s a kinder, gentler Donald Trump waiting in the wings somewhere. But the hard truth is there’s no other Donald Trump.

When he was getting his start in business, Trump was sued by the Justice Department for refusing to rent apartments to black and Latino tenants. Their applications would be marked with a “C” for “colored” and then rejected. Three years later, the Justice Department took Trump back to court because he hadn’t changed.

That pattern continued through the decades.

State regulators fined one of Trump’s casinos for repeatedly removing black dealers from the floor. And let’s not forget Trump first gained political prominence leading the charge for the so-called “birthers.” He promoted the racist lie that President Obama isn’t really a U.S. citizen — part of a sustained effort to delegitimize America’s first black President.

In 2015, Trump launched his own campaign with another racist lie. He described Mexican immigrants as rapists and criminals and accused the Mexican government of actively sending them across the border. None of that is true.

Since then, the steady stream of bigotry has continued.

Trump — the man who today is the standard bearer of the Republican Party — said a distinguished federal judge born in Indiana couldn’t be trusted to do his job because “he’s a Mexican.” Republican House Speaker Paul Ryan described that as “the textbook definition of a racist comment.”

But for Trump, that’s just par for the course.

This is someone who retweets white supremacists online, spreading their message to 11 million people. When asked on national television if he’d disavow the support of David Duke, a former leader of the Ku Klux Klan, Trump wouldn’t do it. He refused to condemn anti-Semitic slurs and death threats coming from his supporters, and he’s continued to push discredited conspiracy theories with racist undertones.

He said thousands of American Muslims in New Jersey cheered the 9/11 attacks. He suggested that Ted Cruz’s father, a Cuban immigrant, was involved in the Kennedy assassination. And just recently, Trump claimed President Obama founded ISIS — and then he repeated that nonsense over and over again.

This man wants to be President of the United States.

Some people will say that Trump’s bluster and bigotry is just over-heated campaign rhetoric, but the policies he’s proposed would put prejudice into practice. He would form a deportation force to round up millions of immigrants and kick them out of the country. He’d abolish the bedrock constitutional principle that says if you’re born in the United States, you’re an American citizen. And he’d ban Muslims around the world — 1.5 billion men, women, and children — from entering our country just because of their religion.

Don’t worry, some will say, as president, Trump will be surrounded by smart advisors who will rein in his worst impulses. But look who he’s put in charge of his campaign: Stephen Bannon, the head of a right-wing website called Breitbart.com.

The de facto merger between Breitbart and the Trump campaign represents a landmark achievement for the “Alt-Right,” a group the Wall Street Journal describes as a loosely organized movement, mostly online, that “rejects mainstream conservatism, promotes nationalism, and views immigration and multiculturalism as threats to white identity.”

No one should have any illusions about what’s really going on here. The names may have changed — racists now call themselves “racialists.” White supremacists now call themselves “white nationalists.” The paranoid fringe now calls itself “alt-right.” But the hate burns just as bright.

This is part of a broader story — the rising tide of hardline, right-wing nationalism around the world.

Just yesterday, Nigel Farage, one of Britain’s most prominent right-wing leaders, campaigned with Donald Trump in Mississippi. This is a man who stoked anti-immigrant sentiments to win the referendum to have Britain leave the European Union. Farage has called for a ban on the children of legal immigrants from public schools and health services, has said women are quote “worth less” than men, and supports scrapping laws that prevent employers from discriminating based on race.

And the godfather of this global brand of extreme nationalism is Russian President Vladimir Putin, who Trump himself heaps praise upon. Trump talks casually of abandoning our NATO allies, recognizing Russia’s annexation of Crimea, and of giving the Kremlin a free hand in Eastern Europe.

All of this adds up to something we’ve never seen before. There’s always been a paranoid fringe in our politics, but it’s never had the nominee of a major party stoking it, encouraging it, and giving it a national megaphone. Until now.

This isn’t just about one election. It’s a moment of reckoning for all of us who love our country and believe that America is better than this.

Twenty years ago, when Bob Dole accepted the Republican nomination, he pointed to the exits and told any racists in the Party to get out. The week after 9/11, George W. Bush went to a mosque and declared for everyone to hear that Muslims “love America just as much as I do.” In 2008, John McCain told his own supporters Barack Obama is an American citizen and “a decent person.”

We need that kind of leadership again.

Every day, more Americans are standing up and saying “enough is enough” — including a lot of Republicans. I’m honored to have their support, and I promise you this: With your help, I will be a President for Democrats, Republicans, and Independents. For those who vote for me and those who don’t. For all Americans.

Because I believe we are stronger together. It’s a vision for the future rooted in our values—and reflected in a rising generation of young people who are the most open, diverse, and connected we’ve ever seen. So let’s keep moving forward together. Let’s stand up against prejudice and paranoia. And let’s prove once again, that America is great because is America is good.