I was thinking of this:

"tokenism n. The policy of making only a perfunctory effort or symbolic gesture toward the accomplishment of a goal, such as racial integration. n. The practice of hiring or appointing a token number of people from underrepresented groups in order to deflect criticism or comply with affirmative action rules. n. A policy of formally complying with efforts to achieve a goal by making small, token gestures; especially to hire a minimal number of ethnically diverse or disadvantaged people"

I'm not saying a black woman in a position of power wouldn't be good. I'm saying it's not enough, because appointing a single black woman doesn't change the underlying structures that result in the incredible bias that prevents black women specifically, and all women generally, getting into politics in greater numbers. I'm saying it's a token gesture because there's no structural change; it would be a 'benevolent' choice by the man in power.