Senator Pat McCarran called the APA "a bill of rights for the hundreds of thousands of Americans whose affairs are controlled or regulated" by federal government agencies.

[7] Beginning in 1933, President Franklin D. Roosevelt and the Democratic Congress enacted several statutes that created new federal agencies as part of the New Deal legislative plan, established to guide the United States through the social and economic hardship caused by the Great Depression.

[8] Professor George Shepard claims that Roosevelt's opponents and supporters fought over passage of the APA "in a pitched political battle for the life of the New Deal" itself.

[9] Shepard notes, however, that a legislative balance was struck with the APA, expressing "the nation's decision to permit extensive government, but to avoid dictatorship and central planning.

[11] Based on one study, Roosevelt commented that the practice of creating administrative agencies with the authority to perform both legislative and judicial work "threatens to develop a fourth branch of government for which there is no sanction in the Constitution."

In 1939, Roosevelt requested for Attorney General Frank Murphy to form a committee to investigate practices and procedures in American administrative law and suggest improvements.

[12] The Final Report defined a federal agency as a governmental unit with "the power to determine... private rights and obligations" by rulemaking or adjudication.

The Final Report made several recommendations about standardizing administrative procedures, but Congress delayed action as the US entered World War II.

Without careful regulation, that can lead to unchecked authority in a particular area of government, violating the separation of powers, a concern that Roosevelt himself acknowledged.

[16] The APA's capacity to hold accountable regulatory business monitors that oversee civil matters that apply "'soft' administrative law" is also limited.

The APA requires that to set aside agency actions that are not subject to formal trial-like procedures (i.e. rulemaking), the court must conclude that the regulation is "arbitrary and capricious, an abuse of discretion, or otherwise not in accordance with the law.