Complex sentence: Pauling had been practically apolitical until World War II. At the beginning of the Manhattan Project, Robert Oppenheimer invited him to be in charge of the Chemistry division of the project, but he declined, not wanting to uproot his family.
Split into simpler sentences: Pauling had been practically apolitical until World War II. At the beginning of the Manhattan Project, Robert Oppenheimer invited him to be in charge of the Chemistry division of the project. However, he declined, not wanting to uproot his family.