We have knowledge about the issues that concern us most. For Politicians, understanding what is noise, and what are real opinions are key to re-election. We do see government responding to changes in political opinion. The publics attitudes toward a given government policy can vary over time, often dramatically. Public opinion places boundaries on allowable types of public policy.
Citizens are willing to register opinions on matters outside their expertise.
Governments tend to react to public opinion. The government sometimes does not do what the people want. Homer Simpson's rules of the school-yard. Always make fun of those different from you. Never say anything, unless you're sure everyone feels exactly the same way you do.