information:classification
Social activism

In 1881, Wallace was elected as the first president of the newly formed Land Nationalisation Society. In the next year, he published a book, Land Nationalisation; Its Necessity and Its Aims, on the subject. He criticised the UK's free trade policies for the negative impact they had on working-class people. In 1889, Wallace read Looking Backward by Edward Bellamy and declared himself a socialist, despite his earlier foray as a speculative investor. After reading Progress and Poverty, the bestselling book by the progressive land reformist Henry George, Wallace described it as "Undoubtedly the most remarkable and important book of the present century."

Wallace opposed eugenics, an idea supported by other prominent 19th-century evolutionary thinkers, on the grounds that contemporary society was too corrupt and unjust to allow any reasonable determination of who was fit or unfit. In his 1890 article "Human Selection" he wrote, "Those who succeed in the race for wealth are by no means the best or the most intelligent..." He said, "The world does not want the eugenicist to set it straight," "Give the people good conditions, improve their environment, and all will tend towards the highest type. Eugenics is simply the meddlesome interference of an arrogant, scientific priestcraft."

In 1898, Wallace wrote a paper advocating a pure paper money system, not backed by silver or gold, which impressed the economist Irving Fisher so much that he dedicated his 1920 book Stabilizing the Dollar to Wallace.

Wallace wrote on other social and political topics, including in support of women's suffrage and repeatedly on the dangers and wastefulness of militarism. In an 1899 essay, he called for popular opinion to be rallied against warfare by showing people "that all modern wars are dynastic; that they are caused by the ambition, the interests, the jealousies, and the insatiable greed of power of their rulers, or of the great mercantile and financial classes which have power and influence over their rulers; and that the results of war are never good for the people, who yet bear all its burthens (burdens)". In a letter published by the Daily Mail in 1909, with aviation in its infancy, he advocated an international treaty to ban the military use of aircraft, arguing against the idea "that this new horror is 'inevitable', and that all we can do is to be sure and be in the front rank of the aerial assassins—for surely no other term can so fitly describe the dropping of, say, ten thousand bombs at midnight into an enemy's capital from an invisible flight of airships."

In 1898, Wallace published The Wonderful Century: Its Successes and Its Failures, about developments in the 19th century. The first part of the book covered the major scientific and technical advances of the century; the second part covered what Wallace considered to be its social failures including the destruction and waste of wars and arms races, the rise of the urban poor and the dangerous conditions in which they lived and worked, a harsh criminal justice system that failed to reform criminals, abuses in a mental health system based on privately owned sanatoriums, the environmental damage caused by capitalism, and the evils of European colonialism. Wallace continued his social activism for the rest of his life, publishing the book The Revolt of Democracy just weeks before his death.