Look closely at the women attending President Trump's address on Tuesday night, and you'll notice something: A lot of them are wearing white.

The clothing choice is meant to represent women's suffrage, according to Rep. Lois Frankel, D-Fla., who leads the House Democratic Women’s Working Group.

"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."

The House Democratic Women's Working Group is made up of the 66 female Democrats who serve in the House of Representatives. The group focuses on women's rights for issues such as affordable health care (including Planned Parenthood) and equal pay.

Not wearing white tonight: Melania Trump, who showed up wearing black.

WASHINGTON, DC - FEBRUARY 28: First lady Melania Trump arrives to a joint session of the U.S. Congress with U.S. President Donald Trump on February 28, 2017 in the House chamber of the U.S. Capitol in Washington, DC. Trump's first address to Congress is expected to focus on national security, tax and regulatory reform, the economy, and healthcare. (Photo by Alex Wong/Getty Images)