For a century, foundations have been sources of private wealth for public purposes; they have committed great resources to address society's ills but they have remained wary of straying too close to the political sphere. Foundations are prohibited from engaging in partisan political activity and from lobbying elected officials about legislation. So foundations have often viewed their funding as a counterweight to public spending, supporting, for example, domestic social services or international public health initiatives.
Yet a notable portion of foundation spending a growing portion for some foundations is targeted almost directly at the political process. This spending is intended to win the "war of ideas" under way in American politics. It supports research and advocacy that aims to influence how elected officials and the public think about a broad range of policies. This "war of ideas" is fundamentally a battle between liberals and conservatives, progressives and libertarians, over the appropriate role for government. Some progressive writers argue that conservatives have been winning battles in the war of ideas because liberal foundations are not spending near the amount that conservative foundations are on the war and the liberal money is not deployed nearly as effectively.