CNN’s Anderson Cooper on Wednesday explained how Donald Trump’s new attack on his Republican 2024 rival Nikki Haley is just the latest racist dog whistle from the former president.

Trump this week attempted to paint his former U.S. ambassador to the United Nations as “less than American” when he highlighted her Indian ancestry by referring to her on his Truth Social platform as “Nikki Nimrada Haley,” said Cooper. Her full name is Nimarata Nikki Haley. Trump also shared a false claim that the South Carolina-born politician might not be a U.S. citizen.

Trump is doing “what he has done so many times before to opponents and adversaries and perceived enemies alike,” said Cooper.

The Republican 2024 front-runner attacked Vice President Kamala Harris in the same way and was one of the biggest pushers of the false Birther conspiracy theory that former President Barack Obama was not born in the U.S.

“Racist dog whistles are just too appealing for him to pass up,” Cooper lamented.