The first time Vice President Joe Biden appeared on The Late Show With Stephen Colbert, he got choked up talking about how his son’s death made him decide that a 2016 presidential run probably was not in the cards for him. A year later, after Donald Trump had bested Hillary Clinton in the general election, he sat down with the host and sounded a lot less hesitant about a 2020 campaign.

Now, another year has gone by and the former veep was back on Colbert’s show Monday night. Inevitably, the topic of him challenging President Trump in the next election came up. But first, they had to talk about Trump.

As recently as March, Biden said that he believed Trump “deserves a chance” to show that he can lead the country. How did he think that was going so far, Colbert wanted to know?

“There are certain things that, when they occur, you just can’t remain silent,” Biden said. “And Charlottesville, for me, was a moment where I thought silence would be complicity.” For Trump not to have an “outright, flat condemnation” of those neo-Nazis marching in the streets was unacceptable for him. “I found it reprehensible,” Biden said. “So I couldn’t remain silent anymore.”

Asked how Trump has changed the office of the presidency, Biden said, “I think, God willing, it will go down as a single exception in American history.” But at the same time, he acknowledged that people are “worried” about how the Trump administration seems to be dismantling democracy as we know it.

“Look, for 74,500 votes, thereabout, we wouldn’t be having this conversation,” Biden said. “We’d have a good president. We’d have a president who understands the role of the presidency.”

Besides talking politics, Biden was on Colbert to promote his new book, Promise Me, Dad, about his son Beau, who died of brain cancer two and a half years ago. “It wasn’t ‘promise me, Dad, that you’ll run for president,’” Biden explained, but rather Beau wanted his father to “stay engaged.” He added, “He really wanted me to run, but that wasn’t the promise.”

Looking back at their first sit-down interview on The Late Show two years ago, Colbert said, “I think one of the reasons why people, you know, two years ago, when we had you on the show, said they’d be very happy if you ran for president is they want someone who shares their humanity and can unite people about common values.”

Colbert knew that he wouldn’t get an answer about whether Biden will jump into the 2020 race, but he couldn’t help but ask anyway. “I honest to God don’t know,” Biden told him, explaining that he still does not feel ready after his son’s death, but left the door open to change his mind.

Biden would also not name any specific names of candidates he thinks could unite voters against Trump, worried he’d “leave somebody out,” but did say the Democrats have some “really talented, relatively new people” in the party.

“Remember, no one knew who Bill Clinton was until about 15 months before he ran, before the general election,” Biden said. “No one knew who Barack—they knew the speech but didn’t have any idea of his presidential aspirations until about a year and a half out, so this is really early in the game.”