WATCH: Tucker Carlson bursts out in maniacal laughter while pushing racist conspiracy theory

On Wednesday evening, after weeks of fierce pushback, Fox News' Tucker Carlson once again pushed the white nationalist "Great Replacement" conspiracy theory — a narrative pushed by extremist groups that there is a deliberate plot to crowd white people out of Western nations and replace them with dark-skinned foreigners. And during the segment, he burst out in angry laughter, responding to criticism of the idea from Rep. Ted Lieu (D-CA).

"Well, Ted Lieu is a member of Congress, he's a Democrat, he represents the state of California, he's really smart, he went to Stanford, so when you hear him speak, you're really hearing the Democratic Party's brain trust on display," said Carlson. "With that in mind, we wanted to bring you one of his more recent pronouncements, a tweet in response to one of his colleagues, Congressman Scott Perry. Now, Perry was making an argument we have often made, because it's true, and that is that Democrats are using mass immigration to transform the country to change who votes so they can control who wins."

"Ted Lieu was VERY annoyed that Scott Perry said this," said Carlson. "And so he sent the following tweet, and he was clearly enraged as he did. Quote, 'Dear @RepScottPerry: Native-born Americans like you are no more American, and no less American, than an immigrant like me.' Good point, we agree with that. And then he said this: 'And with every passing year, there will be more people who look like me in the US. You can't stop it. So take your racist replacement theory and shove it.'"

"In other words, you're being replaced, and there's nothing you can do about it! So shut up!" added Carlson, breaking out in sharp laughter.

Watch below: