NORMAN, Okla. (AP) — President Joe Biden is expected to formally apologize on Friday for the country’s role in the Indian boarding school system, which devastated the lives of generations of Indigenous children and their ancestors.

“I would never have guessed in a million years that something like this would happen,” said Secretary of Interior Deb Haaland, a member of the Pueblo of Laguna. “It’s a big deal to me. I’m sure it will be a big deal to all of Indian Country.”

Shortly after becoming the first Native American to lead the Interior, Haaland launched an investigation into the boarding school system, which found that at least 18,000 children, some as young as 4, were taken from their parents and forced to attend schools that sought to assimilate them, in an effort to dispossess their tribal nations of land. It also documented nearly 1,000 deaths and 74 gravesites associated with the more than 500 schools.

No president has ever formally apologized for the forced removal of Native American, Alaska Native, and Native Hawaiian children — an element of genocide as defined by the United Nations — or any other aspect of the U.S. government’s decimation of Indigenous peoples.

During the second phase of its investigation, the Interior conducted listening sessions and gathered the testimony of survivors. One of the recommendations of the final report was an acknowledgement of and apology for the boarding school era. Haaland said she took that to Biden, who agreed that it was necessary.

Haaland, whose grandparents were forced to attend a boarding school, said she was honored to play a role, along with her staff, in helping make the apology a reality. Haaland will join Biden during his first diplomatic visit to a tribal nation as president on Friday as he delivers his speech. “It will be one of the high points of my entire life,” she said.

It’s unclear what, if any, action will follow the apology. The Department of Interior is still working with tribal nations to repatriate the remains of children on federal lands, and many tribes are still at odds with the U.S. Army Corps of Engineers, which has refused to follow the federal law regulating the return of Native American remains when it comes to those still buried at Carlisle Indian School in Pennsylvania.

“President Biden’s apology is a profound moment for Native people across this country,” Cherokee Nation Principal Chief Chuck Hoskin Jr. said in a statement to The Associated Press.

“Our children were made to live in a world that erased their identities, their culture and upended their spoken language,” Hoskin said in his statement. “Oklahoma was home to 87 boarding schools in which thousands of our Cherokee children attended. Still today, nearly every Cherokee Nation citizen somehow feels the impact.”

Friday’s apology could lead to further progress for tribal nations still pushing for continued action from the federal government, because it’s an acknowledgement of past wrongs left unrectified, something “known and buried,” said Melissa Nobles, Chancellor of MIT and author of "The Politics of Official Apologies."

“These things have value because it validates the experiences of the survivors and acknowledges they’ve been seen and we heard you, and also there’s a lot of historical evidence to suggest this happened,” Nobles said.

In Canada, a country with a similar history of subjugating Indigenous peoples and forcing their children into boarding schools for assimilation, an apology from Prime Minister Justin Trudeau in 2017 was followed by the establishment of a truth and reconciliation process and the injection of billions of dollars into First Nations to deal with the devastation left by the government’s policies.

No such commission exists in the U.S. A bill to establish a truth and reconciliation process was introduced last year by Sen. Elizabeth Warren, but it remains in the Senate.

Pope Francis issued a historic apology in 2022 for the Catholic Church’s cooperation with Canada’s “catastrophic” policy of Indigenous residential schools, saying the forced assimilation of Native people into Christian society destroyed their cultures, severed families and marginalized generations.

“I am deeply sorry,” Francis said to school survivors and Indigenous community members gathered in Alberta. He called the school policy a “disastrous error” that was incompatible with the Gospel. “I humbly beg forgiveness for the evil committed by so many Christians against the Indigenous peoples,” Francis said.

In 1993, President Bill Clinton signed a law apologizing to Native Hawaiians for the overthrow of the Hawaiian monarchy a century prior. In 2008, Australian Prime Minister Kevin Rudd formally apologized to Aboriginal and Torres Strait Islander peoples for his government’s past policies of assimilation, including the forced removal of children. New Zealand Prime Minister Jacinda Ardern made a similar concession in 2022.

Hoskin said he is grateful to both Biden and Haaland for leading the effort to reckon with the country’s role in a dark chapter for Indigenous peoples, but he emphasized that the apology is just “an important step, which must be followed by continued action.”