Never defeated in a union election, McLachlan remained an officer of the miners' union until July 1923, when he was removed by UMW president John L. Lewis for promoting a sympathetic strike in support of Sydney steelworkers.
Reconnu coupable en octobre 1923 d'écrit diffamatoire, il est condamné à passer deux ans au pénitencier de Dorchester, mais il est libéré en mars 1924.