“I think that Plessy v. Ferguson was right and should be reaffirmed.” That’s what Supreme Court law clerk William H. Rehnquist wrote privately in December 1952 to his boss, Justice Robert H. Jackson. When the memorandum was made public in 1971 and Rehnquist’s Supreme Court confirmation hung in the balance, he claimed that the memorandum reflected Jackson’s views, not Rehnquist’s. Rehnquist was confirmed, but his explanation triggered charges that he had lied and smeared the memory of one of the Court’s most revered justices. This Essay analyzes a newly discovered document—a letter Rehnquist wrote to Justice Felix Frankfurter in 1955, criticizing Jackson—that reveals what Rehnquist thought about Jackson shortly after Brown and the Justice’s death. The 1955 letter was not known during Rehnquist’s 1971 or 1986 confirmation hearings. It is also currently missing and may have been stolen from Frankfurter’s Papers at the Library of Congress. This Essay argues that Rehnquist’s 1955 letter represents his disappointment with Brown and the beginning of his outspoken criticism of the Warren Court. The letter, this Essay contends, says less about how Rehnquist felt about Jackson and more about Rehnquist’s disappointment over his Justice’s role in the most important Supreme Court decision of the twentieth century.