In May 1921, Zack was elected a member of the unified Communist Party of America following its formation at a unity convention held at the Overlook Mountain House near Woodstock, New York.

Zack was arrested in the Justice Department-directed operation and was held for about four months, finally released in early 1923 on $5,000 bail.

Zack was chosen as the head of TUEL's National Committee of the Needle Trades Section, which was organized November 22, 1922.

[2] On April 17, 1923, Zack resigned from the CEC of the CPA, which helped make way for Earl Browder, Robert Minor, and Alfred Wagenknecht, coopted to the 10-member body at that time.

Home in the United States with his American citizen wife and New York City-born son still in the USSR,[7] Zack was named the Secretary for the Eastern District of the Trade Union Unity League (TUUL), successor to TUEL.

[8] In the fall of 1934, Zack abruptly quit the CPUSA, ostensibly over the party's departure from the ultra-radicalism of the so-called "Third Period."

Zack briefly joined the Workers Party of the United States (WPUS), formed in 1934 by two small political organizations, headed by pacifist A.J.

Apparently, she was arrested as a relative of an enemy of the people: she served 18 years in Gulag labor camps, while their son grew up in a special home.

In succeeding years, he established himself as an outspoken anti-communist, addressing conservative gatherings and writing on the dangers of Stalin's dictatorship.

On May 1, 1950, in Mosinee, Wisconsin, a local American Legion outpost staged a mock Communist takeover to illustrate what life under Soviet conquest might be like.

Joseph Zack Kornfeder died age 65 of a heart attack while checking into a Washington, D.C., hotel on May Day, May 1, 1963.