She participated in protests for women's right to vote, during which she was attacked by mobs and arrested, until the passage of the Nineteenth Amendment to the United States Constitution.
"[12] She was among a group of women of the Congressional Union for Woman Suffrage (CU), founded in 1913 by Lucy Burns and Alice Paul.
[13] Upon coming to Washington D.C. in 1918, she became Alice Paul's private secretary and participated in suffragist non-violent protests, realizing that she could be arrested and jailed.
Among forty protesters, the group burned papers printed with President Woodrow Wilson's "empty words about democracy".
We, the women of the United States, denied the liberty which you helped to gain, and for which we have asked in vain for sixty years, turn to you to plead for us.At a protest in late 1918, suffragists intended to burn the empty words of anti-suffragist senators in the Senate chambers, but the police confiscated banners and flags from the women and held them for several hours.
[15] In January 1919, her activities were reported in the Colorado Springs Gazette, including "Miss Arnold in Next Watchfire Party at Capitol", followed by news of her arrest and sentencing.
[16] She was arrested at the Watchfires for Justice protest in January 1919, when President Wilson's words about democracy were burned in cauldrons.
[3] She was a National Woman's Party organizer, including her efforts in Florida and New Hampshire,[17] until women received the right to vote with the passage of the Nineteenth Amendment to the United States Constitution[3] on August 18, 1920.
[19] She portrayed Lucretia Mott in an Equal Rights Amendment pageant at the Garden of the Gods in 1923 at Colorado Springs.