It is useful to anticipate such shifts, and sometimes to promote or discourage them. The shifts mean changes in the arenas, actors, and methods of politics, which can aid or hinder particular policies. Each type of politics favors particular interests, and with time is likely to bring about a reaction which shifts the politics. This mechanism of self correction played out when tobacco interests exploited client politics. They created opportunities for entrepreneurs to mobilize public indignation and revolutionize public policy.
Reversals offer opportunities to substantially change policy.
The possibilities warn lobbyists that excesses can prompt sharp reversals, and warn entrepreneurs that victory is fleeting. Economic and political processes operate as markets in shaping public policy, and both undervalue externalities and public goods . Good health is undervalued because its benefits are not concentrated. To some extent the political market works to correct the undervaluing of externalities by the economic markets. Thus governments adopt regulation, taxes, and programs of compensation when the economic market ignores the costs of air pollution or the value of seat belts.