Essentially anyone can contribute to public policy management. When I call up my senator and ask him to approve a bill or look into a particular issue, I am also contributing to public policy making.
Many Americans underestimate their potential contribution in American policy. Most of us feel that next to lobby groups, interest groups and political action committees, we have little say. But I don't think that's true. Like the article said, elected representatives have to answer to, and listen to their constituency. So if the majority of the constituency wants the representative to pursue a particular issue in Congress, then he or she will have to. That's public policy and management!