
Practically no one with a passing knowledge of J. Edgar Hoover would identify the late FBI director with civil liberty protection. Under his decades-long tenure, the FBI routinely violated the law and the Constitution. The Bureau has spent nearly fifty years trying to reinvigorate its reputation and disassociate itself from the dark days of Hoover.
Your typical civil libertarian will probably state that, the greater distance placed between the FBI and the haunting memory of Hoover, the better. But on at least one seminal occasion, J. Edgar Hoover was far more loyal to the Constitution than the incumbent administration.
The U.S. federal government, in addition to governments of other countries with significant populations of Japanese ancestry, such as Canada and Brazil, ordered the relocation of thousands of individuals to internment camps. In the US, internment began pursuant to Executive Order 9066, issued by Franklin Delano Roosevelt on February 19, 1942. Surprisingly, J. Edgar Hoover was flatly opposed. He contradicted the Secretary of the Navy, Frank Knox, when Knox warned about a fifth column of Japanese American saboteurs operating in Hawaii, stating that there was no evidence for this assertion. Hoover plainly stated that “[t]he necessity for mass evacuation is based primarily upon public and political pressure rather than on factual data.” He additionally claimed that “the Army is getting a bit hysterical” in reference to the “extremely unfortunate” evacuation of Japanese Americans.
Hoover’s opposition to mass internment of Japanese Americans did not translate to opposition towards internment in more limited circumstances. Hoover voiced support for interning disloyal Japanese Americans, and later supported the internment of disloyal communists in the years following World War II (Harry Truman, then president, refused to allow this). Nor did it mean that he had a soft spot on race. J. Edgar Hoover famously hired few African Americans to the FBI, and refused to hire Hispanic Americans, believing that they were naturally dishonest and could not handle guns (he believed, by contrast, that they were skilled knife-fighters).

Despite this, Hoover can properly receive some credit for opposing mass internment of Japanese Americans. After all, even the ACLU was divided on the issue at the time. In truth, it’s beyond a significant stretch to say J. Edgar Hoover was a defender of civil liberties, but he was on the right side of history during this tumultuous epoch.
Side note: Hoover’s bizarre hiring practices extended far beyond refusing to hire Hispanics. Hoover even opposed hiring agents with pimples, believing that hiring individuals with facial blemishes would harm the image of the FBI.