Getting the president re-elected is only one of the many, many accomplishments claimed by Morris, who plays both Boswell and Johnson in his memoirs.
Morris lays no claim to getting the president re-elected within his memoirs. 
mnli hypothesis: Morris lays no claim to getting the president re-elected within his memoirs.  premise: Getting the president re-elected is only one of the many, many accomplishments claimed by Morris, who plays both Boswell and Johnson in his memoirs.