Economic action is a redundant phrase. All action is economic. I don’t just mean all rational action, or all human action. I mean all action. Accidental action still relates to the economy. All action is both influenced by and feeds back in to the economy. The term economic action truly is a waste of a word, but it’s undesirable in other ways as well. The term presents a false affordance for contrast with things like political and social action.
Politics is economics by another name. The vote is exactly a form of currency, and the market is exactly a peculiar form of weighted voting system. The political system can be predicted on the grounds of the economy, modeled with economic models, and is itself a determinant of the economy. The two are in no sense separable. Any political forecast which exempts economic considerations suffers from omitted variable bias and vice versa.
Instead, political science and economics are two different approaches within the same broader field of sociology. Sociology is the study of people or society. The motivation for economics and political science is mutually to improve the lives of people, and the subject matter is mutually the social system. The political system in its entirety is exactly society as a whole, and the economy in its entirety is the same. Economics is the study of the allocation of scarce resources and goods. How can such allocation occur in the absence of people? Economics is a social science. Whether it can be simultaneously social and a hard science is another interesting topic, and I am not arguing that economics is in any sense non-rigorous or that the economy as a social thing is necessarily non-deterministic.
Economic interest is not logically distinct from political, social, or charitable interests. If I propose that Senator Joe gave a particular vote because it is in his political interest, it is also surely in his economic interest. The distinction serves either nothing, or, at best, as a means of highlighting or emphasizing a particular framework of thought.
Sociologists love to criticize the heroic assumptions made by some schools of economic thought, and their criticisms are often appropriate. Sociologists employ some different scholastic techniques, but this is only a matter of norm, not necessity. Network theory and ethnography would be great tools for economists and political scientists, we just don’t often use them. Sociologists could just as well continue in their field and adopt the tools of economics.
They would still be sociologists, but I wouldn’t be surprised if they then opted for the title of economist since it pays a bit more.