While campaigning earlier this year, Mr Biden regularly brought up the fact that Trump’s supporters stormed the US Capitol on January 6, 2021, after Mr Biden beat him in the 2020 election.
Mr Biden also frequently quoted Trump as saying there would be a “bloodbath” if he lost – although the Republican said he was talking in the context of electric car imports from China.
Trump has maintained his false claim that the 2020 election was stolen from him, and in the CBS interview Mr Biden accused the former president of trying to install allies in key electoral positions in US states to manipulate counts if the same thing happened again.
“You can’t love your country only when you win,” Mr Biden said.
The ageing president has long framed Trump as a threat to US democracy.
Ms Harris has sometimes echoed that theme, while focusing more on a positive vision in a campaign that has re-energised Democrats, brought in millions of dollars and helped her nose ahead of Trump in opinion polls.