[2] After independence, Lauristin became a member of the illegal Estonian Communist Youth Union and worked as an editor in various underground newspapers and magazines.

In the same year, he joined the Communist Party of Estonia and became a member of the Central Council of the Estonian Workers' General Union.

[1] After the banning of the Communist Party of Estonia, Lauristin was arrested and was one the defendants involved with the trial of the 149 and was sentenced to six years of forced labor.

After the start of the German-Soviet War in the summer of 1941, Lauristin was appointed deputy chairman of the Republican Defense Committee of the Estonian SSR.

According to the historian Mati Õun, he was executed by fellow communist officials for disobeying Stalin's war orders; however, this version is also contested.