There are many stakeholders in the political sphere, including not only voters in certain constituencies but also unions, large corporations, associations of corporations such as the Chamber of Commerce, professional organizations such as the American Medical Association and American Bar Association (the association of lawyers), public employees, and others. Many of these groups are in general opposition to each other, and they often employ professional lobbyists to convince politicians to follow their political agenda.
For example, unions push for higher wages and better working conditions, while businesses tend to want to keep wages stagnant and resist regulation of working conditions. Professional organizations such as the American Medical Association tend to be opposed to health care companies, as health care companies try to regulate payments to doctors (which means that doctors are often paid less and have to submit more complicated bills to insurance companies to get paid). Public employees often want higher pensions, while administrators on the local and state levels want to keep pensions low or choose not to fund them (as the money comes out of state or local government coffers). Politicians on the local, state, and federal levels have to balance the political agendas of the different stakeholders to win office and keep voters in their folds.