Democratic women in Congress made a bold statement at President Trump’s address to Congress Tuesday night by wearing white, a symbol of the suffragist movement.

The effort was led by Rep. Lois Frankel (D-FL), chair of the House Democratic Women’s Working Group. That working group includes all 66 Democratic women members and delegates of the US House of Representatives, many of whom participated in the action.

Update: Watch Trump’s address to Congress: Full video and annotated transcript

“We wear white to unite against any attempts by the Trump administration to roll back the incredible progress women have made in the last century, and we will continue to support the advancement of all women,” Frankel said in a statement. “We will not go back.”

According to the statement, Women’s Working Group members are fighting for women’s rights like equal pay, paid sick and family leave, retirement security, the right to live “lives free from fear and violence,” and access to affordable child care and affordable health care — “including reproductive health services like those offered by Planned Parenthood.”

Hillary Clinton also wore white to defy Trump on more than one occasion

White, purple, and gold were the official colors of the National Women’s Party and the suffragist movement. According to the Congressional Union for Woman Suffrage’s statement of purpose, the colors were chosen deliberately: purple for “loyalty, constancy to purpose, unswerving steadfastness to a cause,” gold for “the color of light and life and “the torch that guides our purpose.” And white, “the emblem of purity, symbolizes the quality of our purpose.”

Clinton wore purple when she gave her concession speech — which was all about staying devoted to causes, even in the face of setbacks and disappointments like the one she had just experienced.

But she wore all white in moments that seemed to signal defiance of Trump — the night she faced off against him in the third and final presidential debate, and the day of Trump’s inauguration. The latter was an especially striking choice on the eve of the Women’s March on Washington — which drew massive crowds of people to remind Trump that, as Clinton once famously said, “women’s rights are human rights.”

Clinton also wore white at several of her most notable moments of the campaign, like the night she officially won enough delegates in the primary to clinch the nomination and the night she officially accepted the nomination at the Democratic National Convention.

Clinton never explicitly said that defying Trump was her motivation, or that she wore white as an homage to suffragettes. But House Democratic women are making it very clear that their motive is to defy Trump — specifically on gender issues.

A woman politician wearing all white has particular historical meaning, one that women who set political milestones have often been conscious of. Geraldine Ferraro wore all white when she became the first woman to accept the vice presidential nomination of a major party in 1984. Shirley Chisholm wore all white in 1969 when she became the first African-American woman elected to Congress, and again three years later when she became the first African-American woman to run for a major party’s nomination for president.

In general, women’s issues are clearly a big motivator for people who oppose President Trump. According to one survey, Trump’s election inspired the majority of Americans to become more politically engaged than they were before — and people were more likely to take action if they were upset by Trump’s leaked comments about sexually assaulting women.