The legislative branch—consisting of the House of Representatives and the Senate--passes laws to enact policy. This branch also helps create federal agencies through enabling acts or statutes. Agencies that are created by acts of Congress—such as the National Labor Relations Board and the Securities and Exchange Commission—help set domestic policy. Typically, the agencies hire experts who study all sides of the issues related to the agency's mission and then recommend policies or policy changes. The legislative branch also confirms the heads of executive branch departments, cabinet secretaries who play a significant role in shaping the policy agenda of the executive branch.

The executive branch, headed by the president, affects domestic policy most directly by issuing executive orders. In addition, the president appoints the secretaries of cabinet-level departments, such as State, Homeland Security, Education, Transportation, and Health and Human Services. These departments and other federal agencies develop rules and regulations and manage the distribution of benefits and services. Just as importantly, their procedures and priorities determine the pace at which a policy is enacted, as well as what form it takes. And these factors can have a dramatic effect on the lives of individual Americans.

The judicial branch does not directly formulate domestic policy, but that doesn’t mean it plays no role in shaping policy. Indeed, the Supreme Courts and the federal courts affect policy indirectly, but profoundly. For example, the Supreme Court in 2015 essentially legalized same-sex marriage in the United States by ruling that an Ohio law banning gay marriage violated the Fourteenth Amendment. In 1954, in Brown v. Board of Education, the Supreme Court decided that state laws allowing segregation by race in public schools were unconstitutional. While the Supreme Court did not propose a specific policy to desegregate public schools, it did through its decision require that such policy be created.