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. Research Polling involves interviewing a sample of citizens to estimate public opinion as a whole. Provides people with a chance to express views about government. Interpret the meanings of elections raise issues. How things were done in the past 1787-1920's straw polls opinions of a friends, congressmen, etc.