The act was signed into law by U.S. President Franklin D. Roosevelt on December 18, 1941, less than two weeks after the Japanese attack on Pearl Harbor.

[1] The act gave the President enormous authority to execute World War II in an efficient manner.

With the act, the President was allowed to censor mail and other forms of communication between the United States and foreign countries.

[1] The Second War Powers Act also repealed the confidentiality of census data, allowing the FBI to use this information to round up Japanese-Americans.

The written delegation was only given in 1944 when Grove's deputy Kenneth Nichols was about to sign a large contract with Du Pont, and it was found that he only had a low delegated authority, as Nichols' higher authority for the Manhattan Project had only been given verbally by General Styer to his predecessor Colonel James C.