Final answer:
Barrington Moore is the scholar who believes class structure is pivotal in determining the type of political regime that is formed, as detailed in his work on the social origins of various government forms.
Step-by-step explanation:
The scholar who credits class structure as the key factor in which type of political regime is formed is Barrington Moore. Moore suggested in his seminal work "Social Origins of Dictatorship and Democracy" that the class structure of a society, and specifically the relationships between landowners, peasants, and the bourgeoisie, has a decisive role in determining the nature of the political system that emerges.
He examined a variety of historical cases to illustrate how these class relationships led to different forms of government, such as democracy, fascism, and communism, in different countries.