Written by Oscar Holland, CNN

Behind him, House Speaker Nancy Pelosi sat in a white suit jacket and blouse. Before him, a block of female lawmakers donned a range of white outfits and visibly unimpressed expressions. Even his daughter Tiffany was pictured in white, with social media speculating that the choice may have been more than a coincidence.

President Trump's State of the Union address was flooded with the color white.

The bold statement, initiated by the House Democratic Women's Working Group , saw dozens of lawmakers coordinate their attire as a show of solidarity among women. Democrats taking part included newly-elected Rep. Alexandria Ocasio-Cortez of New York, who was seen wearing a white cape, and Rep. Ilhan Omar of Minnesota, who wore a white vest and trousers paired with a blue hijab and red shirt.

U.S. Rep. Alexandria Ocasio-Cortez greets fellow lawmakers ahead of the State of the Union address in the chamber of the U.S. House of Representatives on February 5, 2019 in Washington, DC. Credit: Win McNamee/Getty Images North America/Getty Images

Even Rep. Dean Phillips of Minnesota joined the rallying call, turning up to the House Chamber in a white jacket with black lapels, and a button reading "ERA yes," (a reference to the Equal Rights Amendment). Ribbons were reportedly handed out to the less fashion-forward men.

The move laid bare the contrast between the two parties, creating a palpable divide in the chamber while drawing attention to Melania and Ivanka's choice of black outfits. But the role of the color white in US politics predates today's disagreements by more than a century.

Rep. Ilhan Omar of Minnesota wore a white vest and trousers paired with a blue hijab and red shirt. Credit: Win McNamee/Getty Images North America/Getty Images

In particular, the color is associated with the suffragette movement. Early advocates for women's voting rights wore white as a symbol of purity, often alongside purple for dignity and green for hope. The suffragettes also used white to reassure onlookers that their protests were non-aggressive.

According to Rep. Lois Frankel of Florida, the chair of the aforementioned working group, Tuesday's move was a direct nod to the movement.

"Wearing suffragette white is a respectful message of solidarity with women across the country, and a declaration that we will not go back on our hard-earned rights," she told CNN ahead of Tuesday's address.

Female lawmakers cheer Trump at State of the Union

White has continued to serve as symbol for women in politics. Shirley Chisholm, the first African American woman to be elected to Congress, wore white to be sworn in in 1969. Geraldine Ferraro did the same when she was named America's first female Vice President nominee.

In more recent years, Hilary Clinton often donned a white pantsuit, most notably when accepting her party's presidential nomination in 2016.