However, this was the time period when the Conservative Judaism movement was just starting to break away from Orthodoxy, and Friedlander and Kaplan were early students and faculty of the Conservative Jewish Theological Seminary.
The JTS rabbis sought to use Young Israel to establish a youth platform for the Conservative movement, and until the end of World War I, the organization had two groups, the firmly Orthodox, and the more liberal group that worked with the Conservative rabbis.
Their goal was to make Orthodox Judaism more relevant to young Americanized Jews, at a time when a significant Jewish education was rare, and most Orthodox institutions were Yiddish-speaking, and oriented to an older, European Jewish demographic.
They reached a truce in 1918 and agreed to join forces in more than just name, and created a single Young Israel organization, led by Irving Bunim, who would be president of NCYI for many years.
By 1920, Bunim and his Orthodox cohort grew nervous about the Conservative wing and their increasing theological changes.
By the end of World War I, the two Lower East Side groups shared a name, but little else.
The Conservative group promoted the seminars, and the Orthodox group was focused on prayer.
He sought the help of Rabbi Bernard Revel, and was able to convince the entire Young Israel to follow Revel's advice.
Between Revel, and extensive networking by Bunim with other potential Young Israel leaders in the Orthodox community, the Conservative rabbis, particularly Kaplan, were shut out of the entire organization, and the movement became firmly Orthodox.To bolster this success, in 1922 the Orthodox leaders added some basic Orthodox-oriented requirements to the Young Israel charter, such as synagogue requirements for regularly-held services, Torah study, separation of men and women.In 1924, the central group organized a convention for all the other groups that had emulated them (by setting up their own original Young Israel lectures and shuls).Later in the decade, the synagogue network grew to about 25.The central organization developed a Wall Street office with a full-time staff.The young people had taken over the shul, itself a novel experience.