The Writing Center @ The University of Wisconsin - Madison
The Writer's Handbook
An Editing Checklist

6. Incorrect pronoun case

Determine whether the pronoun is being used as a subject, or an object, or a possessive in the sentence, and select the pronoun form to match.

Incorrect:

Castro's communist principles inevitably led to an ideological conflict between he and President Kennedy.

Correct:

Castro's communist principles inevitably led to an ideological conflict between him and President Kennedy.

Incorrect:

Because strict constructionists recommend fidelity to the Constitution as written, no one objects more than them to judicial reinterpretation.

Correct:

Because strict constructionists recommend fidelity to the Constitution as written, no one objects more than they [do] to judicial reinterpretation.