Which individual is personally trying to influence public policy?

You're question isn't completely specific, but if I'm reading correctly I would tell you that interest groups influence public policy through lobbying of their interests.  This is a group of individuals who sign petitions, protest, and voting for example. I hope this helped :)

basic principles: federalism, separation of powers, checks and balances, judicial review, representative democracy, limited government, rule of law, individual rights and responsibilities, consent of the governed, majority rule, popular sovereignty, equal protection.