Complex sentence: First, Donald Rumsfeld and Richard Cheney manipulated their appointments to advance their own agendas within the American political arena; and secondly, Rumsfeld and Cheney convinced Ford to make these chnages in order to improve his re-election prospects against his primary Republican opponent, Ronald Reagan.
Split into simpler sentences: First, Donald Rumsfeld and Richard Cheney manipulated their appointments to advance their own agendas within the American political arena. Or, secondly, Rumsfeld and Cheney convinced Ford to make these changes in order to improve his re-election prospects against his primary Republican opponent, Ronald Reagan.