Former Democratic presidential nominee Hillary Clinton pausing while speaking during a campaign rally last November at the Grand Valley State University Fieldhouse in Allendale, Mich. (Brendan Smialowski/AFP/Getty Images)

Declaring that she is done with being a candidate, former secretary of state Hillary Clinton looked back on the 2016 presidential campaign Sunday with a mix of regret and frustration over the way she thinks President Trump won the election by stoking racial grievances.

"He was quite successful in referencing a nostalgia that would give hope, comfort, settle grievances for millions of people who were upset about gains that were made by others," Clinton said on CBS's "Sunday Morning" ahead of the Tuesday release of her campaign memoir, "What Happened."

Host Jane Pauley replied, "What you're saying is millions of white people."

"Millions of white people, yeah," Clinton said. "Millions of white people."

Clinton, the Democratic Party nominee in 2016, said she will not pursue the party's 2020 presidential nomination.

"I am done with being a candidate," Clinton said. "But I am not done with politics because I literally believe that our country's future is at stake."

Her remarks on Sunday came a little more than a year after she gave a major campaign speech in which she described the "disturbing" connection between Trump's campaign and the alt-right, a small, far-right movement that seeks a whites-only state.

"He is taking hate groups mainstream and helping a radical fringe take over the Republican Party," Clinton said in Reno, Nev., last year. "His disregard for the values that make our country great is profoundly dangerous."

Trump responded at the time by saying that Clinton was using the "oldest play in the Democratic playbook."

"She paints decent Americans, you, as racists," Trump told a crowd in Manchester, N.H., after her speech.

In the Sunday interview, Clinton criticized Trump's inaugural address, which she said she attended in January out of a sense of duty, as a speech that spoke to the anger of some white voters.

"I'm a former first lady, and former presidents and first ladies show up," Clinton said. "It's part of the demonstration of the continuity of our government. And so there I was, on the platform, you know, feeling like an out-of-body experience. And then his speech, which was a cry from the white-nationalist gut."

Clinton's remarks on Sunday came a little more than a year after she gave a major campaign speech in which she described the "disturbing" connection between Trump's campaign and the "alt-right," a movement associated with white nationalism.

"He is taking hate groups mainstream and helping a radical fringe take over the Republican Party," Clinton said in Reno, Nev., last year. "His disregard for the values that make our country great is profoundly dangerous."

Trump responded at the time by saying that Clinton was using the "oldest play in the Democratic playbook."

"She paints decent Americans, you, as racists," Trump told a crowd in Manchester, N.H., after her speech.

Clinton said on Sunday that she will not pursue the 2020 Democratic presidential nomination.

"I am done with being a candidate," Clinton said. "But I am not done with politics because I literally believe that our country's future is at stake."

Clinton also criticized Trump's preparedness for the White House.

"We have a reality show that leads to the election of a president. He ends up in the Oval Office. He says, 'Boy, it's so much harder than I thought it would be. This is really tough. I had no idea,' " Clinton said. "Well, yeah, because it's not a show. It's real. It's reality, for sure."

The former Democratic nominee said she has moved on from her election loss but acknowledged that the sting of defeat has not entirely faded away.

"I am good," Clinton said. "But that doesn't mean I am complacent or resolved about what happened. It still is very painful. It hurts a lot."