The men instantly became martyrs to the anarchist movement, and de Cleyre channeled her outrage at the “infamy” of the trial and executions into a vigorous endorsement of anarchism, speaking annually at Haymarket memorials and returning to the subject again and again in her writings.

“The question ‘Why I am an Anarchist,’ ” she wrote in 1897, “I could very summarily answer with, ‘because I cannot help it.’ ”

Beyond her activism, De Cleyre had many romantic entanglements but none were fully satisfying, , according to a biographer, Paul Avrich. The labor activist Dyer D. Lum, who was 27 years her senior, was the first man to treat her as an intellectual equal, but he left her heartbroken when he took his own life. She bore her only child, Harry, with James B. Elliot, a carpenter who was a believer in the writings of the freethinker Thomas Paine. Yet eventually she pushed both away, reluctant to be a mother or wife.

The assassination of President William McKinley by the anarchist Leon Czolgosz in 1901 unleashed a wave of anti-anarchist sentiment. When Senator Joseph R. Hawley of Connecticut offered $1,000 to anyone who shot an anarchist, de Cleyre responded with a letter telling him to save his money; he could kill her.

“I will stand straight before you at any distance you wish me to, and you may shoot, in the presence of witnesses,” she wrote. “Does not your American commercial instinct seize upon this as a bargain?”

The following year de Cleyre had her own brush with an assassin. A former student of hers who had become romantically obsessed with her shot her in a jealous rage. She survived, and then worked for his release on her recovery.

“It would be an outrage against civilization if he were sent to jail for an act which was the product of a diseased brain,” she wrote.