Joe Biden began a broadside at the Democrat debate on Wednesday against President Donald Trump’s proclivity for tweeting, before giving up mid-sentence.

Biden, along with Sen. Bernie Sanders (I-VT), was asked if it was appropriate for Democrat voters to chant, “lock him up” in reference to Trump. The former vice president claimed that Democrats should not lower themselves to the level of division that Trump and his supporters have gone to since 2016.

“I don’t think its a good idea that we model ourselves after Trump and say, ‘lock him up.’ Look, we have to bring this country together. Let’s start talking civilly to people and tweeting — the next president who starts tweeting, anyway,” the former vice president stopped mid-sentence to laughter from the audience.

Despite Biden’s lofty rhetoric about being civil, the former vice president has consistently attacked Trump on and off the campaign trail. In August, Biden compared Trump to the Ku Klux Klan, claiming the president had used “dog whistle” language to signal it was acceptable to be racist.

“This is a president who has said things no other president has said since Andrew Jackson,” Biden told Anderson Cooper during an interview on CNN. “Nobody’s said anything like the things he’s saying.”

“We went through it after the Civil War in terms of the Ku Klux Klan and white supremacy,” the former vice president added. “This is about separating people into the good and bad in his mind. It’s about an access to power, its a trait used by charlatans all over the world … divide people, pit them against one another.”