The Associated Press The president of one of the largest Native American tribes in the U.S. announced Tuesday he has removed responsibilities from his vice president, saying she no longer represents his administration and should consider resigning from the highest office within the Navajo Nation to ever be held by a woman. Navajo Nation President Buu Nygren made the announcement in a news conference that was broadcast on social media. The tribe has been mired by political upheaval since April, when Navajo Vice President Richelle Montoya publicly outlined allegations of intimidation and sexual harassment within the administration. An independent investigation of Montoya’s claims was initiated while other opponents of Nygren began collecting signatures from voters across the reservation — which spans parts of Arizona, New Mexico and Utah — as…