In the past week, as a swirl of sexual assault accusations against Donald J. Trump has prompted a loud national discussion about male power and women’s rights, the first woman to be a major party’s presidential nominee was barely heard from.

Though Hillary Clinton has stood at the center of feminist debates for more than two decades, she has at times been an imperfect messenger for the cause. That has never been more apparent than now, as her old missteps and her husband’s history have effectively paralyzed her during a moment of widespread outrage.

The most impassioned speeches on the topic have come not from her, but from the first lady, Michelle Obama, who said Mr. Trump’s words had “shaken me to my core,” and from President Obama and others. When Mrs. Clinton herself spoke, she quickly changed the subject to other groups of people Mr. Trump had insulted, and she tried to lighten the mood with a joke about watching cat videos.

“It makes you want to turn off the news. It makes you want to unplug the internet or just look at cat GIFs,” Mrs. Clinton told donors in San Francisco on Thursday, making her first remarks on Mr. Trump’s treatment of women since several came forward to accuse him.