Earlier this month, my colleagues and I at the Knight First Amendment Institute at Columbia University secured the release of 96 previously withheld opinions authored by the Justice Department’s Office of Legal Counsel (OLC). We obtained the opinions, all of which date from the last year of Richard Nixon’s presidency, in connection with an ongoing Freedom of Information Act lawsuit. A close look at the memos underscores the significant role the OLC has played, and continues to play, in shaping executive branch policy.

Since its creation in 1933, the OLC has been developing a system of law largely out of the public’s eye. Occasionally described as the “Supreme Court of the Executive Branch,” the OLC answers important and often controversial questions of government power, ranging from questions of executive privilege, to civil rights enforcement, to surveillance authority. The OLC itself explained in 2010 that its “core function … is to provide controlling advice to Executive Branch officials on questions of law.”

Because of the central role OLC opinions play in shaping government policy, many (including the Knight Institute, where I work) have called on the OLC to adopt a policy of presumptively publishing its opinions, with only narrow exceptions for classified or other sensitive information.

Recent OLC opinions — like those determining whether whistleblower reports must be transmitted to oversight committees or whether presidential advisors can be compelled to testify before Congress — highlight the importance of the agency and its memos to public understanding of government.

But the OLC’s older opinions are also important. The recently released opinions from 1974 have much to tell us — not only about the end of the Nixon administration and the first months of Gerald Ford’s presidency, but also about the ways in which the OLC has served as a site for the development of legal theories and doctrine with continuing relevance today.

Take, for example, the recently released memo written in January 1974 on whether a president could be subpoenaed in state court. Months earlier, the D.C. Circuit had rejected the president’s argument that he did not have to comply with a federal grand jury subpoena. Now the president was confronted with a subpoena from a state court. The OLC suggested that Nixon should buttress the standard presidential immunity arguments — rejected by the D.C. Circuit in the earlier case — with the argument that he was immune from state process because of federal supremacy concerns. Ultimately the proceedings were dismissed for other reasons, and the OLC’s arguments were never tested in court.

But the questions that the OLC addressed in the January 1974 memo are before the Supreme Court right now. Last week, the Supreme Court heard argument in a trio of cases stemming from President Trump’s attempt to quash subpoenas for his personal records. In one of those cases, Trump v. Vance, the president has argued that the Supremacy Clause of the constitution immunizes him from complying with state and local criminal process — advancing precisely the theory contemplated by the OLC’s 1974 memo.

The Nixon-era OLC memos also continue to influence the development of new executive branch policy through the OLC’s internal “system of precedent.” A best practices memo from 2010 instructs OLC attorneys to “give great weight” to the conclusions reached in past OLC opinions and cautions them not to “lightly depart” from that precedent. OLC opinions thus frequently rely on past opinions to establish points of law, even when those opinions are not public.

The opinions written in 1974 have been cited in a variety of subsequent memos, including on the reach of the Emoluments Clause, the president’s power to extend reporting deadlines set by statute, and eligibility requirements for the Inspector General of the Department of Defense. The release of historical memos provides important context for more recent OLC opinions and allows those outside the agency to better analyze those decisions.

The publication of the 96 Nixon-era memos is a milestone, and the memos will be immensely useful to historians, journalists, and scholars of presidential power. These opinions reveal previously unknown details about major historical incidents, shed light on the development of legal theories and internal OLC precedent, and make public the law that continues to shape the public’s daily interactions with the government. They serve as a reminder of the significant role the OLC has played in the executive branch for decades and illuminate legal issues that are still debated today. Their release underscores why disclosure, not secrecy, should be the norm for the OLC’s written opinions.