[1] In 1905 became a founding member of the Intercollegiate Socialist Society (ISS),[1] a national organization dedicated to advancing the study of socialism on college campuses around the country through lectures, debates, and publications.

Upon his graduation from law school in 1910, he was named Secretary of the ISS, serving as well as editor of its magazine, The Intercollegiate Socialist, from the time of its launch in 1913.

The name change marked a shifting of orientation, from an exclusive concentration upon college campuses to bringing socialist ideas to trade unions and the general public.

Thomas was a fellow New Yorker born in the same year as Laidler, and the pair shared a middle-class upbringing and a rather academic and technocratic view towards the American Socialist movement.

During the faction fight between a Left Wing loyal to Thomas and an organized Old Guard faction that wracked the Socialist Party from 1934 to 1936, Laidler played a key role for the young insurgents, running for and winning election as State Secretary of the Socialist Party of New York in a hotly contested race with Old Guard leader Louis Waldman.