Bernie Sanders stood by Hasan Piker. Moderate Democrats warned against extremism in the party. They think the party must abandon extreme views.

CNN's Abby Phillip asked Sanders about James Carville and Hasan Piker. She wanted to know which one Sanders would choose.

Sanders said it's not a tough choice. He told Carville to start his own party if he doesn't like the current one.

Sanders talked about the Michigan Senate race. He endorsed Abdul El-Sayed, who campaigned with Hasan Piker. El-Sayed won the primary.

Hasan Piker and Abdul El-Sayed made fun of James Carville. They said he was making it easier for them to win.

Bernie Sanders and James Carville are shown in a photo. They have different opinions about the Democratic Party.

Abdul El-Sayed campaigned with Hasan Piker. He appeared on Piker's YouTube channel.

Bernie Sanders said people can choose which party they want. He thinks the Democratic Party should include people like Piker.

Sanders asked if people want to be in a party that takes money from big companies. He thinks the party should stand up to these companies.

James Carville did not respond to a request for comment. He has strong opinions about the Democratic Party.

A think tank said Democrats lost power because they seemed extreme. Voters think the party is more extreme than the Republicans.

The think tank warned that embracing extreme views will hurt the Democrats. They think it will help the Republicans.

Hasan Piker was criticized for his comments about Hamas. Human rights groups condemned his statements.

Hasan Piker is a streamer and creator. He appeared at a conference in Vancouver, Canada.

Bernie Sanders was asked about Hasan Piker's comments. Piker said America deserved 9/11, which was a controversial statement.

Sanders said Piker's statement was dumb. But he thinks Piker has many good ideas and should not be canceled.

Sanders said everyone says things they regret. He thinks people should look at the big picture and move forward.

Hasan Piker later said he did not mean America deserved the 9/11 attacks. He defended his statement as a critique of US foreign policy.

A think tank said Republicans will use Hasan Piker's extreme views against the Democrats. They think it will hurt the party's chances.

The think tank said Democratic candidates need to win over moderate voters. They think embracing extreme views will hurt their chances.

James Carville worries about the end of the two-party system. He thinks the rise of Democratic socialists is a problem.

James Carville said he would not be in the same party as Hasan Piker. He thinks Piker's views are too extreme.

Carville said he would leave the party if Piker becomes a force in it. He does not want to be associated with Piker's views.

Carville predicted that one of them would leave the party. He thinks it's unlikely they can work together.

Carville said he cannot predict the future. But he knows he and Piker will not be in the same party.

Hasan Piker and Abdul El-Sayed made a video together. They talked about James Carville's comments and the Democratic primary.

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Hasan Piker said James Carville is making it easier for them to win. He thinks Carville's comments are helpful.

Hanna Panreck is an associate editor at Fox News.