He was a leader in the movement to abolish child labor. He carried on an active propaganda for the general adoption of the juvenile court plan, and for political and social reform, through lectures delivered in many American and foreign cities and through the publication of books and pamphlets, of which "The Beast" (with Harvey J. O'Higgins, 1910) was widely circulated. In 1906, Judge Lindsey was a candidate for Governor of Colorado, and in 1912 became a member of the Progressive National Committee.