No participant controls the full process. A group may place an issue on the agenda but fail to assemble votes. A president may focus public attention without persuading Congress. Congress may enact broad language while agencies shape practical meaning through implementation. Courts can invalidate unlawful action but ordinarily cannot supply the money, staffing, or political cooperation required for a replacement program. Influence also varies by stage: media attention and public mobilization may be especially important during agenda setting, while organized specialists often gain leverage during technical formulation and rule implementation.

Resources work through mechanisms. Legislators have votes and oversight powers; presidents have agenda visibility, a veto, appointments, and executive direction within law; agencies have expertise and administrative capacity; groups have information, organization, and access; media have publicity and framing; citizens have votes, participation, and opinion. Possessing a resource does not guarantee success. Information may be discounted as biased, a veto threat may lack credibility, intense public attention may fade, and an agency may lack statutory authority for its preferred solution.

Consider a proposal to change military procurement. Contractors and watchdog groups supply competing information; committees write authorization and funding provisions; the president recommends priorities and directs administration; defense agencies purchase equipment; journalists investigate performance; and courts address any proper legal dispute. Public reaction may raise the electoral cost of continuing or ending the program. On an exam, identify the actor's actual resource and trace it to a specific stage. Visibility is not authority, and influence over one choice is not control of the entire policy outcome.

Video lesson: Introduction to the public policy process | US government and civics | Khan Academy