The color is a reference to the suffragists who fought for women to have the right to vote. Former Secretary of State Hillary Clinton wore white for her speech at the Democratic National Convention for the same reason, and many of her supporters wore white to the polls on Election Day.
“It’s really important to show that what candidate Trump said about women and the way that he has behaved toward women in the past is not an acceptable standard for a president,” Democratic Rep. Linda Sanchez of California told the Los Angeles Times about the protest.
You can see how the protest looked inside the House chamber on Tuesday in the photo above. House Minority Leader Nancy Pelosi also tweeted an image of the group beforehand: