American women gained the right to vote in 1920. So why does “Votes for Women: A Portrait of Persistence,” opening Friday at the National Portrait Gallery, start in 1832 and go all the way up to 1965?

“The 19th Amendment didn’t wrap things up in a pretty bow,” says Kate Clarke Lemay, who curated the exhibit, which is being mounted as part of the Smithsonian’s American Women’s History Initiative “Because of Her Story.” “It didn’t resolve the disenfranchisement of women for everybody. Black women, Native American women — any minority woman — still had all of these impediments to their voting rights until 1965,” when the Voting Rights Act was passed.

The irony of that lies in the fact that black women were instrumental in the beginning of the women’s suffrage movement. Many of the early leaders — black and white — were abolitionists, who often used the strategy of humanizing enslaved people to call attention to the inhumanity of slavery.

“So I started in 1832, which was when The Liberator, an abolitionist newspaper, published an illustration of [an enslaved woman] asking, ‘Am I not a woman and a sister?’ ” Lemay says. “It’s basically pointing out her humanity. [Early suffragettes] were radicalized by the abolitionist movement.”

While the exhibition does showcase related artifacts, it’s the portraits of the suffragettes (examples are above) that make up the bulk of what visitors will see. “Portraits are powerful because they give a feeling of a relationship, or a bridge through time,” Lemay says. “You can see these beautiful dresses they’re wearing; they cared about the dignity of sitting for a portrait. They wanted to make sure they looked dignified because they were being accused left and right of not being dignified.”

The exhibition includes examples of those accusations.

Thomas Nast — the guy who invented our modern idea of Santa Claus — drew a caricature portraying Victoria Woodhull, who ran for president on a third-party ticket in 1872 and promoted ideas like non-monogamy and women’s equality in matters relating to marriage, in a very unflattering light. “Her hair is crazy; she’s got this hairdo that makes her look like she has horns on her head,” Lemay says. “And then, mixed in with these wings — she clearly looks like a demon.”

“Votes for Women” is about history, of course, but it also occupies a unique place in today’s world of museum exhibits. “I don’t know how often a major museum has put on an exhibition where you walk through the galleries and the only things you see are women,” Lemay says. “I mean, there’s not a single man in the show — unless it’s a husband."

National Portrait Gallery, Eighth and F streets NW; Fri. through Jan. 5, free.