Do political parties or interest groups have the greatest impact in determining and shaping public policy?

Both political parties and interest groups play significant roles in shaping public policy, but their impact can vary depending on the context. Political parties often establish broad policy agendas and influence legislation through their control of government institutions. In contrast, interest groups can exert focused pressure on specific issues, mobilizing resources and public opinion to advocate for particular policies. Ultimately, the greatest impact may depend on the political climate and the specific issues at hand.