"There are certain things that, when they occur, you just can't remain silent, and Charlottesville, for me, was a moment where I thought silence would be complicity," Biden said in an interview on "The Late Show With Stephen Colbert" on Monday.
"To not have an outright, flat condemnation of that … I thought the silence was deafening," he added.
Trump faced harsh criticism from political leaders — Democrats and Republicans alike — over his initial response to the rally and his failure to call out neo-Nazis and other hate groups by name.
Asked if he thought Trump's time in the Oval Office might influence future presidencies, Biden said, "I think it will, God willing, go down as the single exception in American history."
"I mean, I just think there's an attack on the system, and I think people are worried, and by the way, and it goes beyond President Trump, in my view," he added.
Biden, 74, told NBC News' "Today" show on Monday that he hadn't made up his mind about whether to run for the Democratic presidential nomination in 2020.
"I'm not closing the door. I've been around too long," he said. "I'm a great respecter of fate."
"But who knows what the situation is going to be a year and a half from now? I don't have any idea," he added.