The USSR was one of the world’s two imperialist superpowers from the end of WW2 in 1945 to its collapse in 1991. As a socialist whose political education was in a broadly Cliffite tradition, I would not describe the USSR as a socialist society at all, given it lacked pretty much all the key criteria of socialism such as “democracy” and “there being no state because it withered away” and “having no class distinctions”. Instead I would view the Soviet Union as a state capitalist society, one which was engaged in militaristic competition with the West, and acted as a colonial power in regions on the country’s periphery, like Kazakhstan. This despite the genuineness of the original Russian Revolution – basically I would see that as having been defeated by counterrevolution, like so many other revolutions before and afterwards.