stylistic:style_transfer, quality:correction
The FBI, McCarthyism, and trial

During the 1950s, the U.S. government's anti-communist McCarthyism campaign targeted Du Bois because of his socialist leanings. Socialist historian Manning Marable characterizes the government's treatment of Du Bois as "ruthless repression" and a "political assassination".

The FBI began to compile a file on Du Bois in 1942, investigating him for possible subversive activities. The original investigation appears to have ended in 1943 because the FBI was unable to discover sufficient evidence against Du Bois, but the FBI resumed its investigation in 1949, suspecting he was among a group of "Concealed Communists". The most aggressive government attack against Du Bois occurred in the early 1950s, as a consequence of his opposition to nuclear weapons. In 1950 he became chair of the newly created Peace Information Center (PIC), which worked to publicize the Stockholm Appeal in the United States. The primary purpose of the appeal was to gather signatures on a petition, asking governments around the world to ban all nuclear weapons.

In United States v. Peace Information Center, 97 F. Supp. 255 (D.D.C. 1951), the U.S. Justice Department alleged that the PIC was acting as an agent of a foreign state, and thus required the PIC to register with the federal government under the Foreign Agents Registration Act. Du Bois and other PIC leaders refused, and they were indicted for failure to register. After the indictment, some of Du Bois's associates distanced themselves from him, and the NAACP refused to issue a statement of support; but many labor figures and leftists – including Langston Hughes – supported Du Bois.

He was finally tried in 1951 and was represented by civil rights attorney Vito Marcantonio. The case was dismissed when the defense attorney told the judge that "Dr. Albert Einstein has offered to appear as character witness for Dr. Du Bois". Du Bois's memoir of the trial is In Battle for Peace. Even though Du Bois was not convicted, the government confiscated Du Bois's passport and withheld it for eight years.