NORMAN, Okla. (AP) — President Joe Biden is preparing to issue an historic apology during his first diplomatic visit to a tribal nation as president on Friday. He’s planning to formally apologize for the nation’s 150-year campaign to assimilate Indigenous children by taking them away to Indian boarding school system. The system devastated the lives of generations of Indigenous children and their ancestors. Secretary of Interior Deb Haaland says this is a big deal to all of Indian County. She launched an investigation that found nearly 1,000 children died at more than 500 schools during U.S. government efforts to dispossess tribal nations of their land.