The Anti-Defamation League (ADL) has called upon the Republican Party’s presumptive nominee, Donald Trump, to formally renounce the support of American Freedom Party head William Daniel Johnson.

Johnson, an attorney and white nationalist leader who has endorsed Trump’s candidacy, was initially selected as a delegate for California’s upcoming GOP primary.

Writing under a series of pen names, Johnson has advocated what has been referred to as the “James O. Pace” Amendment to the US Constitution. Under Johnson’s proposed amendment, all non-Aryans, with the exception of Native Americans and Hawaiians, would be deprived of citizenship and deported from the United States.

The Trump campaign’s original delegate slate for California included Johnson but later claimed his inclusion was the result of a “database error”.

A local Trump campaign director, Tim Clark, emailed Johnson, telling him that his selection was an error and asking him to step down from the position.

“They made a mistake,” Johnson told the Guardian. “They removed me, and that’s fine.”

Despite an initial report, however, that the Trump campaign was unable to alter its slate after the deadline, as of Sunday, Johnson’s name did not appear on the delegate list.

The ADL has insisted that the Trump campaign openly condemn Johnson and renounce his support.

“The American Freedom Party is a hate group that ADL has been tracking for years,” ADL CEO Jonathan Greenblatt said. “We call on Donald Trump to renounce the support of the American Freedom Party and to remove its leader, William Johnson, from the Trump delegate slate in California.”

Other celebrities listed on Trump’s California delegate list include House Majority Leader Kevin McCarthy, Israeli-American television producer Daphne Barak, and Paypal founder Peter Thiel.