Peace activism
After their return to Austria, Suttner continued her journalism and concentrated on peace and war issues, corresponding with the French philosopher Ernest Renan and influenced by the International Arbitration and Peace Association founded by Hodgson Pratt in 1880.
In 1889, Suttner became a leading figure in the peace movement with the publication of her pacifist novel, Die Waffen nieder! (Lay Down Your Arms!), which made her one of the leading figures of the Austrian peace movement. The book was published in 37 editions and translated into 15 languages. She witnessed the foundation of the Inter-Parliamentary Union and called for the establishment of the Austrian Gesellschaft der Friedensfreunde pacifist organisation in an 1891 Neue Freie Presse editorial. Suttner became chairwoman and also founded the German Peace Society the next year. She became known internationally as the editor of the international pacifist journal Die Waffen nieder!, named after her book, from 1892 to 1899. In 1897, she presented Emperor Franz Joseph I with a list of signatures urging the establishment of an International Court of Justice and took part in the First Hague Convention in 1899 with the help of Theodor Herzl, who paid for her trip as a correspondent of the Zionist newspaper, Die Welt.
Upon her husband's death in 1902, Suttner had to sell Harmannsdorf Castle and moved back to Vienna. In 1904 she addressed the International Congress of Women in Berlin and for seven months travelled around the United States, attending a universal peace congress in Boston and meeting President Theodore Roosevelt.
Though her personal contact with Alfred Nobel had been brief, she corresponded with him until his death in 1896, and it is believed that Von Suttner was a major influence on his decision to include a peace prize among those prizes provided in his will. Bertha von Suttner was awarded the Nobel Peace Prize on 10 December 1905. The presentation took place on 18 April 1906 in Kristiania, what is now Oslo, Norway.
In 1907, Von Suttner was the only woman to attend the Second Hague Peace Conference, which mainly pertained to the law of war. Von Suttner was actually highly critical of the 1907 conference and warned of a war to come. When she accepted her Nobel Peace prize a year earlier, she had said: "(…) whether our Europe will become a showpiece of ruins and failure, or whether we can avoid this danger and so enter sooner the coming era of secure peace and law in which a civilisation of unimagined glory will develop. The many aspects of this question are what the second Hague Conference should be discussing rather than the proposed topics concerning the laws and practices of war at sea, the bombardment of ports, towns, and villages, the laying of mines, and so on. The contents of this agenda demonstrate that, although the supporters of the existing structure of society, which accepts war, come to a peace conference prepared to modify the nature of war, they are basically trying to keep the present system intact".
Around this time, she also crossed paths with Anna Bernhardine Eckstein, another German champion of world peace, who influenced the agenda of the Second Hague Peace Conference. A year later she attended the International Peace Congress in London, where she first met Caroline Playne, an English anti-war activist who would later write the first biography of Suttner.
In the run-up to World War I, Suttner continued to campaign against international armament. In 1911 she became a member of the advisory council of the Carnegie Peace Foundation. In the last months of her life, while suffering from cancer, she helped organise the next Peace Conference, intended to take place in September 1914. However, the conference never took place, as she died of cancer on 21 June 1914, and seven days later the heir to her nation's throne, Franz Ferdinand was killed, triggering World War I.
Suttner's pacifism was influenced by the writings of Immanuel Kant, Henry Thomas Buckle, Herbert Spencer, Charles Darwin and Leo Tolstoy (Tolstoy praised Die Waffen nieder!) conceiving peace as a natural state impaired by the human aberrances of war and militarism. As a result, she argued that a right to peace could be demanded under international law and was necessary in the context of an evolutionary Darwinist conception of history. Suttner was a respected journalist, with one historian describing her as "a most perceptive and adept political commentator".