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When House of Representatives released the so-called “Nunes memo” Friday, the news was one more step in a wave of controversy that has called into question the relationship between U.S. intelligence and the nation’s elected officials.

The GOP memo, produced by the House Intelligence Committee under committee chair Rep. Devin Nunes, contains allegations that suggest misconduct in the FBI’s investigation of Russian interference in the 2016 election. The decision to release it, against the wishes of the FBI and some politicians in both parties, represents a major shift in intelligence oversight, the process through which Congress and others are able to check the actions of agencies such as the FBI.

But the world of intelligence oversight wasn’t always so fraught. For much of the nation’s history, intelligence gathering proceeded largely with bipartisan support and little questioning. That began to change in the last several decades.

Some of that change was witnessed firsthand by Loch K. Johnson, in roles that included staff director of the Subcommittee on Intelligence Oversight for the House Permanent Select Committee on Intelligence. He was also special assistant to the chairman of the Senate Select Committee on Intelligence and then a staff aide on the Senate Foreign Relations Committee in the mid-1970s, just as the Church Committee was investigating possible misdeeds in the course of federal intelligence-gathering.

He’s now Regents Professor of Public and International Affairs at the University of Georgia and the author of the new book Spy Watching: Intelligence Accountability in the United States. He spoke to TIME shortly before the memo was declassified on Friday about why the release of the controversial document is such big news.