It’s often noted, in coverage of President Trump’s firing of James Comey as head of the FBI, that the generous 10-year term for FBI directors — longer than two presidential terms — is intended to insulate them from political interference. Since the term was established by law in 1976, only one other FBI director has been fired — William S. Sessions — and he used an FBI plane for personal travel, among other improprieties. That’s one reason many observers find the firing of Comey so disturbing, particularly coming as it did amid a high-profile investigation of the president’s associates.

But some historical context complicates the picture. The law establishing the 10-year term was only passed in 1976, a few years after J. Edgar Hoover’s death. And Hoover, of course, effectively held a lifetime appointment. Many presidents were sorely tempted to fire him during his epic and near-dictatorial reign over the FBI from 1924 to 1972, yet none dared. So while today we think of the 10-year term as lengthy — and as a protection from partisanship — it was originally a reassertion of congressional power over an office that had become too powerful: in effect, a term limit.

History also shows that the issue of hiring and firing FBI directors has always been problematic, and the past offers no firm guidelines for future conduct. Before the FBI became the FBI in 1935, its various precursor agencies saw tumultuous leadership. And for all the talk of the “norm” of a 10-year term, only one FBI director has served a full decade since that norm was established: Robert Mueller, who served under Presidents George W. Bush and Obama for a dozen years, and who is now returning as special counsel.  

The unruly early years

The roots of the FBI as an organization stretch back to the Reconstruction period, when the Secret Service moved temporarily over from the Treasury Department to the Justice Department in 1871, in order to combat the Ku Klux Klan. The director of this fleeting FBI precursor, Hiram Whitley, did a fine job. In South Carolina alone in 1872, there were 1,207 arrests, 96 prosecutions, and convictions of 86 Klansmen who went to prison.

But the white South loathed Whitley. His enemies in Washington finally forced him to resign in 1874, on the pretext that he’d committed financial irregularities. The Secret Service went back to Treasury, and for the remainder of the century, the White House had to rely on ad hoc arrangements for federal law enforcement.

A second FBI precursor sprang up in 1908, when President Theodore Roosevelt decided to crack down on Congress members who, it was widely known, were engaged in Western land fraud. Exploiting the terms of the Homestead Act of 1862, corrupt speculators were using dummy settlers to acquire rich tracts of forested land. As later proved in court, Sen. John H. Mitchell (R-OR) and Rep. John N. Williamson (R-OR) were paid off for supplying the political protection.

Precisely to avoid congressional involvement — that is, interference — Roosevelt’s Justice Department established the Bureau of Investigations, under Stanley W. Finch, during a congressional adjournment. (Roosevelt’s opponents in Congress accused the president of trying to establish a police state. In typical aggressive style, he retorted that his opponents were criminals trying to get off the hook.)  

Thus, partly because it was set up precisely to investigate legislators, Congress missed the chance of being influential at the birth of the organization that eventually became the FBI. There was no legislative debate on how long a director should serve, or how he should be appointed or dismissed.

An early focus of the BOI was also enforcing violations of the Mann Act, the anti-prostitution and anti–sex slavery law that the bureau gradually expanded to apply to an array of moral offenses. Congress finally took its revenge on Finch in 1913 by starving his specialist anti-prostitution unit of funds, once again charging financial irregularity — and forcing his retirement. The real gripe of the states’ rights Southern bloc of senators was that Finch’s men had operated across state lines.  

In the absence of more specific provision, such as the term limit Congress created in 1976, the hiring and firing of FBI directors is governed by the Constitution. Under Article II, the president has the power to appoint and, as confirmed in the Supreme Court case Myers v. United States in 1926, the implied power to remove. Since 1973, the Judiciary Committee has conducted hearings on appointments to the FBI directorship, and the Senate must approve, but the chief executive can fire whenever he wants to (unless, say, doing so might impede an investigation).

The long shadow of J. Edgar Hoover

Hoover came into office because of the disgrace and demise of his predecessor. At the time of the Teapot Dome scandal, when public officials leased oil-rich US Navy lands in Wyoming to speculators in exchange for bribes, FBI Director William J. Burns investigated the congressional investigators instead of the crime. Sen. Smith W. Brookhart argued that FBI agents were looking for dirt on his colleagues to inspire “government by blackmail.” It all came out, and Burns, as well as Attorney General Harry Daugherty, had to resign.

Once promoted to director, Hoover succeeded in avoiding being fired for 48 years. As has often been noted, presidents were cautious about dismissing a man who knew so much about everybody and might not be above blackmail. But the picture is more complicated than that. Hoover really knew how to play the political game.

In 1933, a group of Southern Democratic senators who were important to the political plans of the newly elected president, Franklin D. Roosevelt, decided they wanted to remove Hoover; once again, the KKK was a factor. Hoover had presided over a new effort to curb the power of the white terrorist group, which the Southerners resented. As part of a complex deal between the incoming administration and Hoover’s congressional opponents, Hoover remained in office but appointed 100 new agents — white, male, and almost all from the South, an episode that would help explain the FBI’s subsequent sluggishness in enforcing civil rights.

In 1961, liberal supporters of John F. Kennedy, the newly elected president, expected him to fire Hoover, who by this time had become an icon of conservatism because of his disrespect, real and perceived, for the civil rights of African Americans, gay people, and the holders of left and liberal views generally. This time, JFK’s political instincts saved the day for Hoover — the president kept him on in the spirit of national unity and to reassure conservatives.

Ten years later, when the FBI was dragging its feet in the effort to silence Pentagon Papers whistleblower Daniel Ellsberg, President Richard Nixon was of a mind to fire Hoover. This time, Hoover did have some embarrassing wiretaps about Henry Kissinger and talked of using them. Nixon said he didn’t think the FBI director would resort to blackmail, but nevertheless deemed it prudent to keep the 76-year-old in office. But it was a close call: By some accounts, Nixon had prepared a statement announcing Hoover’s termination in September 1971, and summoned him to the White House to deliver the news. Then he flinched.

By the time of Hoover’s death two years later, the atmosphere in Washington had changed. New information had emerged about the FBI’s civil rights malpractices in the 1970s — its politically motivated harassment of the feminist, gay, civil rights, and anti–Vietnam War movements. For the first time, public opinion was turning against the bureau. In that context, Hoover’s longevity in office had become an issue of widespread concern.

The birth of the 10-year term

The FBI felt the heat. In congressional testimony in December 1975, William Ruckelshaus, who had been briefly acting director of the FBI and was now assistant attorney general, conceded that Hoover had been too powerful, and suggested that a director’s term should be limited to eight or nine years. Amending the 1968 Omnibus Crime Act in October 1976, Congress opted for 10.

It was not a foregone conclusion that President Jimmy Carter would retain Nixon’s choice for a successor to Hoover, Clarence M. Kelley, the first FBI director to be confirmed by the Senate. But Carter saw a need to depoliticize the FBI, at a moment when fallout from Watergate continued. So he kept Kelley on, even though he was in trouble for partisan reasons.

What were those reasons? By mid-decade, the Democrats were in charge of congressional inquiries into the misdeeds of the CIA and FBI, and they roasted Kelley when he misleadingly (though apparently unwittingly) claimed the FBI had stopped conducting illegal break-ins in the mid-’60s. (They’d continued into the ’70s.) On top of this, there was the affair of the valances (as it was called at the time): It is not the job of the FBI to install window drapes in the home of its director, but they did for Kelley at his house in Bethesda, Maryland, and he got caught out.

Kelley repaid the government some $355. Carter, who had endorsed the idea of a 10-year term, let the wounded director continued at the FBI until February 1978, when Kelley retired. He was succeeded by William H. Webster, who was just 11 months short of his 10-year FBI term when he moved over to head the CIA.

President Bill Clinton in 1993 moved more aggressively to dismiss an FBI director who used FBI resources for personal gain. William Sessions’s abuses were more serious. He had been President Ronald Reagan’s selection in 1987 and had another four years to go under the tenure rule. The firing has often been mentioned during debate over James Comey’s dismissal, but it is not really an instructive comparison. Sessions had used FBI cars and planes to visit his daughter, and even had firewood transported to his house. Few fought hard for his retention, perhaps because he’d lost the support of some agents over his aggressive efforts to increase the numbers of women and members of minority groups in the bureau.

The 10-year rule appeared to be a dead duck. Yet it had enjoyed support in other quarters — similar provisions had been proposed for the NSA and CIA directorships in the 1970s, by the Church Committee (though never passed). And in the decade of Sessions’s dismissal, Europol, regarded by some as a European Union imitation of the FBI, came into existence — with a 10-year tenure rule for its director.

The FBI case (partial political insulation) versus the CIA situation (whipping boy)

When pondering the vulnerability of FBI directors, something might be learned from the president’s historical relationship with CIA directors. There has long been a tacit understanding that when something went wrong with foreign policy, you fired the director of the CIA. President Kennedy authorized the Bay of Pigs operation of 1961 and at first took “sole responsibility” for its failure, but he soon pushed the CIA director, Allen Dulles, to resign.

It is easier to scapegoat a CIA director than an FBI director because he knows less about you, and the rapid turnover of CIA directors since the 1970s speaks for itself. (After 2005, the director of central intelligence — who oversaw all foreign intelligence — was replaced at the top of the bureaucracy by the director of national intelligence, even as the CIA kept its own director.)

There is, however, another presidential response to agency failure: rewarding that failure. The miserable inadequacy in intelligence that led to 9/11 was very much in evidence at the FBI, but President George W. Bush decided not to fire its director, Mueller (who, to be fair, had taken office just a few days before). It proved to be more expedient to blame the preceding Democratic administration for starving the FBI of funds, and to boost massively the money and powers at the FBI’s disposal.

With continuity and unity in mind, President Barack Obama renewed Mueller’s contract at the end of his term (with the Senate’s consent), and the Republican director remained in office for 12 years, the first since Hoover to survive a decade in office. Obama even appointed a Republican, Comey, to succeed him, only to be let down when Comey meddled in the 2016 election in a way that scuppered Hilary Clinton’s chances.

If you consider CIA and FBI history jointly, it is evident both that the agencies have meddled in politics and that they have been meddled with in a highly political way. Judged against the historical record, neither Comey nor President Donald Trump appears to have been at variance with tradition in their political interventions. The FBI director’s job is not as insulated from politics as we’ve been led to believe. But unlike J. Edgar Hoover, Comey got the politics wrong in a way that got him fired. It remains to be seen whether Trump, too, has taken his meddling a step — or more —  too far.

Rhodri Jeffreys-Jones is the author of The FBI: A History. His new book, We Know All About You: The Story of Surveillance in Britain and America, is due out in June 2017.

The Big Idea is Vox’s home for smart discussion of the most important issues and ideas in politics, science, and culture — typically by outside contributors. If you have an idea for a piece, pitch us at thebigidea@vox.com.

Most people familiar with 20th-century history know that it’s not unprecedented for an FBI director to become embroiled in politics. But the popular understanding of the FBI’s intervention into electoral affairs typically extends only to J. Edgar Hoover’s surveillance of civil rights groups and other leftist organizations. In reaction to the revelations about Hoover and the reform initiatives that followed, a series of FBI directors tried to put the bureau on a more neutral footing. It’s that relatively recent tradition of neutrality that James Comey’s election-destabilizing announcement of a further investigation into Hillary Clinton’s email trail has been accused of violating.

But the FBI and its precursor organizations have never been above the political fray. A review of the bureau’s history can help us to place Comey’s actions into context. The bureau is, after all, the servant of the people in a democracy, and it would be strange if were able to achieve utter detachment during political and social controversies that split the public.

Known as the FBI only since 1935, the bureau has a history that really stretches back to President Abraham Lincoln’s last Cabinet meeting in 1865, when he established the Secret Service within the Treasury Department. In the 1870s, the Justice Department took over the Secret Service on a temporary basis and gave it the task of eliminating the Ku Klux Klan, which at the time was running a full-on terrorist campaign against black emancipation.

The Secret Service chief, Hiram C. Whitley, (he was 2 inches taller than Comey, who stands 6-foot-8) succeeded in stamping out the Klan of those days — on behalf of the Republicans who then controlled the White House and Senate. Southern Democrats were furious and eventually took up against all forms of federal policing, as they gained power. (Against this background, the FBI has always been reluctant to acknowledge the creditable anti-Klan element in its pedigree.)

An agency, run by a literal Bonaparte, accused of spying on legislators

Following Reconstruction, with the South reintegrated into the Union and politically potent once more, there was a long interval before the Justice Department once again became the home of a federal detective agency. Wanting to investigate western land fraud, President Theodore Roosevelt in 1908 established the Bureau of Investigation, the direct precursor of the FBI. He had to do it during a congressional adjournment, for there were howls of protest that his intent was to continue spy on legislators. (Indeed it was, said Teddy R., because some of you are criminals!)

In the eyes of the critics, this was a Republican president abusing Democrats, encroaching on states’ rights, and exhibiting European-style dictatorial tendencies. It did not help that the attorney general’s name was Charles Bonaparte and that he was a descendent of Napoleon’s brother.

As is well known, the bureau became involved in that acutely political phenomenon of 1919-’20, the (first) Red Scare. It thus moved in the conservative direction that is associated with the leadership of J. Edgar Hoover, who directed the anti-radical division before heading the bureau from 1924 until his death in 1972.

Born and raised in Washington, DC, then a culturally Southern town, Hoover recruited heavily in the South, a circumstance that enhanced its special agents’ reputation for being socially conservative. Hoover was, however, politically astute. For example, he took up anti-communism when that was fashionable but put it on the back burner in more tolerant times. In election campaigns, he was careful to appear to be apolitical and nonpartisan. To ensure his bureau’s long-term survival as well as his own, he could not afford to alienate either of the main political parties.

Hoover nevertheless took calculated risks. The Penn State historian Doug Charles showed in his book J. Edgar Hoover and the Anti-Interventionists (2007) how, in the years before World War II, the FBI spied on and harassed leading politicians — targeting, for example, Sen. Gerald P. Nye (R-ND). He had criticized what he saw as the role of the armaments industry in shaping foreign policy and advocated US neutrality. With no objections from President Franklin D. Roosevelt, the FBI opened Nye’s mail and looked (in vain) for opportunities to charge him with fraudulent activities. Historians have dealt leniently with Hoover and FDR on this issue only because America entered a war and won it, and because history belongs to the victors. If politics had taken a different turn, Hoover would have been finished.

A failed attempt to throw the 1948 presidential election

After the war, it didn’t take long for Hoover to return to his old ways. In the 1948 presidential campaign, his FBI leaked to Gov. Thomas E. Dewey, the Republican challenger, compromising information about President Harry Truman’s former association with the Kansas City political machine of the corrupt boss Tom Pendergast. The details soon found their way into Republican campaign literature. Why did Hoover allow the leak? Well, his nose was out of joint because Truman had just established the CIA, drawing away some of the powers the FBI chief had wanted for himself.

Furthermore, Dewey was a famous prosecuting attorney who might have smiled on the FBI, and Hoover made the miscalculation, as did so many pundits, that the Republican candidate was a shoo-in for the presidency. Truman won, whereupon Hoover undermined the rest of his administration and the 1952 presidential campaign of the next Democratic candidate, Adlai Stevenson, by aiding and abetting the anti-red, anti-gay, and anti-black hysteria of the day. It was a hysteria that played into the hands of a transformed Republican Party, bitter in the later 1940s after many years out of office, for whom Lincoln had become a memory best left unarticulated.

Where the Truman-Dewey case is concerned, comparison might be made with an incident in British history that affected the fate of the first Labour government, led by Prime Minister Ramsay MacDonald. A few days before the general election of 1924, a cabal within MI-6 (the British foreign intelligence service) and the Conservative Party falsely authenticated the “Zinoviev letter,” allegedly written by Grigory Zinoviev, a Soviet Comintern official. In the letter, Zinoviev appeared to urge Labour voters to agitate for revolution and prepare the way for bolshevism in the United Kingdom. There was too little time before the election to prove the letter to be the forgery it was. It received sensational publicity, and Labour lost. Clearly, the tendency of security agencies to intervene in the politics of democratic nations is not an exclusively American problem.

Nothing happened to the director of MI-6 when the Zinoviev letter was discovered to have been a fraud: He could distance himself from his subordinates, secretive British officialdom would not even admit the existence of MI-6, and, after all, the new Conservative government had been a beneficiary of the fraudulent intervention.

But in the US case, why did Truman not fire Hoover? Perhaps it was because the popular and public relations–savvy director had become a national treasure, and because in a period of tension with the Soviet Union it would have seemed unpatriotic to dismiss a red-baiter.

A new push for neutrality after the MLK revelations

Since the 1950s, the FBI has engaged in a great deal of political espionage. Senate investigations in the 1970s revealed a catalog of abuses, ranging from the harassment of Martin Luther King Jr. to surveillance of the feminist movement. What helped save the bureau in the aftermath of those revelations was a reforming Republican attorney general, Edward Levi, who imposed on it a respected set of guidelines insisting on more neutral behavior. President Ronald Reagan later undid much of that, for example by allowing the FBI a free hand to enter the premises of dozens of Christian and other organizations viewed as critical of his foreign policy, but by this time American politics had entered a more conservative phase, and the bureau’s stock rose.

After 9/11, Republicans claimed, not implausibly, that President Bill Clinton’s administration had allowed the FBI to atrophy. This and the limitations placed on its powers in the name of civil liberty (with Democratic legislators to the fore in that effort) accounted, Republicans argued, for its inadequate performance in failing to predict the Twin Towers attack. The Republican Bush administration resorted to a time-honored remedy, the reward of failure. By boosting the FBI’s budget and expenditure, it hoped to strengthen national security — but it also gained politically by implying the inadequacy of preceding Democratic administrations.

Today’s political debate has focused on the timing of James Comey’s announcement about the new developments in his bureau’s Clinton email investigation. Could he have made his announcement after the election, or maybe earlier to allow the news to be properly digested? Labour Party supporters from 1924 would rise from their graves to agree with those suggestions. Comey’s supporters point to the time it took to develop custom software to weed out Clinton-relevant messages from others on Anthony Weiner’s computer.

But the timing does seem to have been either a political miscalculation or, worse, a political calculation. That does not make it historically unique. Knowing there are precedents for FBI interference in elections, however, hardly makes the situation any more reassuring.

Rhodri Jeffreys-Jones is the author of The FBI: A History, as well as the forthcoming We Know All About You: The Story of Surveillance in Britain and America, due out in June 2017.

The Big Idea is Vox’s home for smart, often scholarly excursions into the most important issues and ideas in politics, science, and culture — typically written by outside contributors. If you have an idea for a piece, pitch us at thebigidea@vox.com.