Another is that of Tony Cliff, associated with the International Socialist Tendency and the British Socialist Workers Party (SWP), dating back to the late 1940s. Unlike Johnson-Forest, Cliff formulated a theory of state capitalism that would enable his group to remain Trotskyists, albeit heterodox ones. A relatively recent text by Stephen Resnick and Richard D. Wolff, titled "Class Theory and History", explores what they term "state capitalism" in the former Soviet Union, continuing a theme that has been debated within Trotskyist theory for most of the past century.