From Critiques Of Libertarianism
Rather than starting from the many definitions of public choice offered by its enemies, I’ll begin with the definition provided by one of its major proponents. As described by the late Charles Rowley, longtime editor of the journal Public Choice, the public choice approach is a ““program of scientific endeavor that exposed government failure coupled to a programme of moral philosophy that supported constitutional reform designed to limit government.” In other words, it is not a neutral research program, but one that has a clear political philosophy and set of aims. Bluntly put, it starts from governments bad, markets good, and further assumes that the intersection between governments and markets (where private interests are able to “capture” government) is very bad indeed.
Henry Farrell, "“Public” choice"