… is from page 93 of the first volume (“Rules and Order,” 1973) of F.A. Hayek’s brilliant Law, Legislation, and Liberty :
In fact, what everywhere is the ultimate power, namely that opinion which produces allegiance, will be a limited power, although it in turn limits the power of all legislators. This ultimate power is thus a negative power, but as a power of withholding allegiance it limits all positive power. And in a free society in which all power rests on opinion, this ultimate power will be a power which determines nothing directly yet controls all positive power by tolerating only certain kinds of exercise of that power.
It it not too much of a simplification to say that the political forces identified by public-choice scholarship  push government to serve special-interest groups at the expense of society at large up to, but not past, the limits imposed upon government power by public opinion.
Think of public opinion as setting the boundaries, on one hand, of what government must do and, on the other hand, of what government can get away with doing. The forces identified by public-choice scholars – most notably, the special-interest-group effect – ensure that government fills the space within these boundaries. But the boundaries themselves are determined by public opinion; they are determined by the prevailing ideas and ideologies – by what Deirdre McCloskey calls people’s “habit of the lip ” (that is, how we talk and what we say to each other). If public opinion changes so, too, do these boundaries. These boundaries can together shift, or widen or narrow, so that the set of activities that government ‘must’ do as well as the set of activities that it can get away with doing both change and, depending upon just how public opinion changes, become either larger or smaller.
At the end of the day, changing government policy in whatever way you deem desirable requires a change in public opinion. Changing the identity of political office-holders will do only very little. People impatient for the world to conform more to their liking do not like this conclusion; such people want change to come quickly. So do I. But reality isn’t optional. Such change does not come quickly – or, more precisely, cannot and will not come any more quickly than the speed at which public opinion changes.
So if you want to change public policy from its current expanse and direction, your only hope is to do whatever you can to change the climate of ideas.