Republicans aren't surprised at all that Undersecretary of State Patrick Kennedy is in the middle of the latest Hillary Clinton email scandal, since Kennedy has been in the GOP crosshairs for the last four years for other Clinton controversies.

FBI notes released Monday indicated that Kennedy offered a trade with the FBI in order to downgrade a classified email from Clinton's private server. But Republicans pointed out Tuesday that Kennedy was involved in two earlier scandals.

For example, Kennedy oversaw security for U.S. diplomatic compounds around the globe leading up to the Benghazi attacks in 2012, which led to the death of four Americans, even as he managed the telecommunications operations that allowed Clinton to use a private email server for official business.

"Patrick Kennedy was at the heart of the State Department's effort to stonewall" our investigation into the Benghazi attacks, Rep. Mike Pompeo, R-Kan., told the Washington Examiner Tuesday, recalling how that GOP-led House probe uncovered Clinton's use of a private email server. "[Kennedy] was also at the heart of her efforts to set up a private email system."

What's so stark in the alleged quid pro quo example, Pompeo argued, is that Kennedy's pressure appeared to be focused on leveraging his power for the sole purpose of covering up for Clinton.

"It's about naked power," Pompeo said. "You can disagree about whether something should be classified or not but … this is just something about power — I've got something you need. You need to put FBI agents in Iraq. It's as egregious an example of State Department tolerating corruption as I have seen," he said.

The 67-year-old Kennedy has spent more than 44 years at the State Department, serving six secretaries in Republican and Democratic administrations since 1993, one of the longest serving officials in the agency's history. His senior post holds sweeping authority, and he serves as the point person for diplomatic security, budget and planning, computer systems, consular affairs and human resources.

To the frustration of his GOP critics, Kennedy also has a knack for self-preservation. He survived 13 hours of grilling as part of the House Select Committee on Benghazi's $7 million investigation, as well as a deposition at the Justice Department by the conservative watchdog group Judicial Watch in June.

"The guy has nine lives," a former diplomat told Foreign Policy earlier this year. "Everything just bounces off him."

That was before FBI documents surfaced alleging that Kennedy engaged in detailed discussions about a potential trade in which State would expand the number of slots for FBI agents in Iraq, in exchange from declassifying a Clinton email.

The State Department, FBI and even President Obama have dismissed the allegations as simply untrue, pointing out that the FBI never provided the "quo" – that the email in question retained its "secret" classification, and both agencies looked into the allegations and found them without merit.

But GOP lawmakers and Donald Trump aren't convinced, arguing that Kennedy and possibly others engaged in blatant illegal behavior to cover up for Clinton's email mistakes.

"In a court of law, somebody's impression at the time that they wrote it down is much more powerful than somebody's recollection after the fact," Matt Whitaker, a former federal prosecutor who runs the nonprofit Foundation for Accountability and Civic Trust, or FACT.

"I would trust the FBI's [interview notes] a lot more than anything that Patrick Kennedy would recall now," added Whitaker, who served as a U.S. attorney during the Bush administration and ran for a U.S. Senate seat in Iowa as a Republican in 2014.

Republican chairmen are promising hearings and subpoenas when Congress returns after the election, and conservative-leaning ethics groups are focusing their ire on Kennedy.

"The latest allegations about Mr. Kennedy's quid pro quo with the FBI raise serious questions about his impartiality," Cause of Action Institute Vice President John Vecchione told the Examiner. "The public deserves openness and honesty from its government officials, not an entrenched political operative who's willing to exert his influence to shield political friends. This is particularly so when the classification of documents available to the public is at stake."

Here's a look at some of the most controversial moments of Kennedy's tenure at State over the last several years.

Kennedy appeared to know and approve of Clinton's private email server from the start of her time at the State Department.

An email exchange when Clinton was just starting as secretary of State in early 2009 discusses plans to provide Clinton a separate computer to skirt the internal State Department computer network.

Kennedy readily signed off on plans between Clinton chief of staff Cheryl Mills and another senior State Department official to set up a "stand-alone PC" across the hall so Clinton can check her emails through a separate, non-State Department computer.

"The stand-alone separate network PC is a great idea," Kennedy wrote to Mills and Lewis Lukens, former deputy assistant secretary of State, according to emails obtained through a Judicial Watch Freedom of Information Act lawsuit.

Kennedy sent or received at least 50 email messages from Clinton's private email address.

Kennedy maintained that he never "focused on" Clinton's use of a private email account for official business even though he said he received 50 to 75 emails from Clinton's hrdr22@clintonemail.com"> hrdr22@clintonemail.com personal address during her four years at State.

"It did not register as — it did not strike any bells in my mind, no," he said later. Kennedy said when he received the emails, "I was focused on responding to the query that I had received," which included responses to the Benghazi attacks and the evacuation of the U.S. embassy in Tripoli.

The admission came during a sworn deposition in Judicial Watch's civil lawsuit brought under the Freedom of Information Act. The transcript of the admission was released in July.

Republicans accuse Kennedy of rigging the State Department's Accountability Review Board, or ARB.

The ARB was intended to provide a review of the State Department's decision to keep Ambassador Christopher Stevens and other U.S. personnel in Benghazi nearly a year after the death of Muammar Qaddafi.

After a three-months-long review of Stevens' communiqués about the increasingly dangerous security situation and top State Department officials responses, the ARB concluded that "no credible evidence" existed pinning "relevant" security decisions in Benghazi to anyone above the assistant secretary level. The finding essentially cleared Clinton, as well as Kennedy, of any culpability for the death of Stevens and other Americans at the Benghazi diplomatic compound.

Rep. Darrel Issa, R-Calif., who chaired the House Oversight and Government Reform Committee at the time, issued a report blaming Kennedy the ARB's findings.

"Under Secretary for Management Patrick Kennedy supervised the selection of the Benghazi ARB staff," he said in the report. "This placed the staff in a position in which their duties required them to evaluate the performance of supervisors, colleagues and friends."

Kennedy defended himself during a House Foreign Affairs Committee hearing. "I had absolutely nothing to do with the assignment of staff to the board," he said.

But Ambassador Thomas Pickering, the chairman of the ARB, appeared to contradict Kennedy, testifying that the State Department provided the staff for the ARB.

"I spoke with Under Secretary Kennedy about the timing [of the committee's report], and he asked me for some ideas about how and what way the ARB should be conducted," he said.

A State Department internal watchdog accused Kennedy of shutting down an investigation involving allegations of child prostitution.

In 2013, Aurelia Fedenisn, a 26-year veteran government investigator who served in the State Department's inspector general's office, accused Kennedy of shuttering an investigation into allegations that U.S. Ambassador to Belgium, Howard Gutman patronized prostitutes, including minors, while at his post in Brussels.

It was just one of several State Department IG investigations that Kennedy is accused of influencing, manipulating or shutting down entirely, according to an internal State IG memo, first reported on by CBS News in June 2013.

Gutman, according to the memo, "routinely ditched… his protective detail" in order to "solicit sexual favors from prostitutes."

Sources told CBS News that after the allegations surfaced, the ambassador was called to Washington, D.C. to meet with Kennedy, but was permitted to return to his post.

Kennedy denied meddling in any way with the investigations, arguing that "I have never once interfered, nor would I condone interfering, in any investigation."