English doesn’t have a singular personal pronoun that is gender-neutral. The only universally accepted singular personal pronouns in English are "he" and "she" (subjective), "him" and "her" (objective), and "his" and "her" (possessive).
During much of the 20th century, most teachers would have advised me to use "his" in talking about the candidate. Masculine pronouns, they would have argued, can refer to people of both genders. Today, however, many readers would consider this usage inaccurate, biased, and confusing.
AND YET MORE CONTROVERSY
Also, some people don’t identify as either "he" or "she," so even "his or her" may not be inclusive of all potential candidates. Plus, writing "his or her" might make my sentence cumbersome.