U.N. cultural and scientific agency UNESCO has announced that the United States plans to rejoin — and pay more than $600 million in back dues — after a decade-long dispute sparked by the organization’s move to include Palestine as a member. U.S. officials say the decision was motivated by concern that China is filling the gap in UNESCO policymaking. The U.S. government has presented a plan for paying the arrears in order to rejoin. UNESCO’s director informed ambassadors of the U.S. decision in a special meeting Monday. The U.S. was once the agency’s biggest funder. Its official return is expected to face a vote by UNESCO’s 193 member states next month.