Presumptive Democratic presidential nominee Joe Biden said about "10-15pc" of people are "just not very good people", but they account for a minority in a country that is overwhelmingly virtuous.
"Do we really think this is as good as we can be as a nation?" Mr Biden said.
"I don't think the vast majority of people think that. There are probably anywhere from 10-15pc of the people out there that are just not very good people. But that's not who we are. The vast majority of people are decent. We have to appeal to that."
His comments came in a virtual town hall with young Americans that was hosted by his campaign and joined by the actor Don Cheadle. The former vice president fielded questions from several young African Americans. The discussion addressed issues of race and police violence.
Mr Biden began his remarks with a mention of George Floyd, a 46-year-old black man who died on May 25 after a white police officer in Minneapolis knelt on his neck as he cried out that he could not breathe.
Mr Biden said that as a white man, he cannot fully understand what it is like to be a black man facing danger in encounters with law enforcement. He called the moment a "wake-up call" to address "systemic racism".
Later, one man posed a question to Mr Biden: "If it is true that you can't lead people if you don't love people, how would he lead differently as a president, specifically for black Americans?"
"Because I love people," Mr Biden responded.
A few minutes later, he alluded to President Donald Trump.
"How many of your friends do you know who have children, who when the president comes on there, they pull them away from the TV?"
Repeating a declaration he has used in recent days, Mr Biden said: "Hate didn't begin with Donald Trump. It's not going to end with him."
Mr Biden then posed the question of whether the nation was as good as it could be.
Past nominees have stoked controversy with blanket descriptions of people.
In 2016, Democrat Hillary Clinton claimed that half of Trump's supporters fit into a "basket of deplorables".
After a backlash, Ms Clinton said she regretted her words.
As a candidate and throughout his presidency, Mr Trump has frequently used divisive rhetoric, including anti-immigrant and anti-Muslim comments, and he even praised some participants in a deadly rally by white-supremacists in Charlottesville, Virginia.
He has often painted a dark picture of the country, portraying it as overrun by crime, violence and malevolence.
Mr Biden, by contrast, has frequently expressed optimism about the country's future, even as it confronts what he has described as a difficult moment. (© Washington Post)