The Yezhovschina threatened to destabilise the state and industry and administration suffered so Yezhov was used of a scapegoat. He was accused of excessive zeal in organising the Terror so in November he was replaced by Beria his deputy.
The 18th Party Congress declared that the ‘mass cleansings were no longer needed’.Around 327 000 released from the gulags and Yezhov arrested and shot in 1940.
Trotsky was assassinated in 1940 so by the end of 1940 all of Stalin's potential rivals had gone and the quashing of sentences restored some faith in the state. Yezhov was seen as culpable for the purges and therefore Stalin had absolute control.