In February, a federal judge took the highly unusual step of ruling that State Department officials and aides to Hillary Clinton should be questioned under oath about her use of a private email server, a controversy that has dogged the presumptive Democratic presidential nominee for more than a year.

In comments from the bench, a visibly frustrated Judge Emmet Sullivan complained about the fragmentary way that new revelations about Clinton’s email use have come to light—largely through press reports and leaks and her shifting explanations for why she set up the server in her New York home rather than use an official “.gov” account when she was secretary of state.

“This is a constant drip… That’s what we’re having here, you know, and it needs to stop,” Sullivan said. He ruled that Judicial Watch, a conservative watchdog group that had brought a lawsuit seeking answers about Clinton’s email server, could question six officials and top Clinton aides about why the email system was set up in the first place and how it was used. Transcripts of those interviews must be made public.

Judicial Watch celebrated the ruling. It would like to see that drip turned into a rushing stream, one that might carry Clinton away for good. And depositions of Clinton’s closest associates and colleagues are a powerful means to unearth new information and ensure that the controversy over her email system doesn’t fade from the headlines.

The saga of Clinton’s email has become the candidate’s biggest single point of vulnerability, and the question of whether she might be indicted in the affair is her own sword of Damocles. While criminal charges seem less likely by the day, Judicial Watch, which has pursued Clinton and her husband in court for years, has guaranteed that the political threat of the email issue won’t subside. The many lawsuits the group has filed under the Freedom of Information Act (FOIA) seeking information about Clinton’s time at the State Department are guided by a single-minded thesis: That the former secretary and potential commander-in-chief is one of the most corrupt and untrustworthy politicians in America today.

“Mrs. Clinton clearly has no respect for the rule of law,” Tom Fitton, Judicial Watch’s president, said in an interview last month with The Daily Beast at his offices in Washington. There’s not a lot of gray area in Fitton’s world view. Clinton and her husband have become masters at “using public office for personal gain,” Fitton said, through their high speaking fees, book advances, and contributions to their foundation, which to him represent a kind of pay-for-play whereby foreign officials and business executives buy the Clinton’s influence. As Fitton sees it, the Clintons are an object lesson in the political capitalism that has come to define contemporary public service.

“The fact that they are a success is an indictment of Washington,” he said.

Judge Sullivan hasn’t decided whether Clinton herself will have to sit down with Judicial Watch’s lawyers. Meanwhile, transcripts of those depositions are providing fodder for journalists and Clinton’s political opponents, and they continue to raise questions about whether her “homebrew” server may have exposed classified information to hackers or foreign spies.

As fortuitous as this case has become for Judicial Watch, it’s not the outcome that the group could have envisioned. Judicial Watch brought the case in 2013 seeking records related to senior Clinton aide Huma Abedin’s employment arrangement. While she was working at State in 2012, Abedin, who has been described as a surrogate daughter to Clinton, was allowed to hold three other jobs—at the Clinton Foundation, in Clinton’s personal office, and with a consulting firm tied to the Clinton family.

Judicial Watch was on the hunt for evidence of a conflict of interest or special favors being done for Clinton friends. But in March 2015, The New York Times revealed the existence of Clinton’s private email account, and that she was using it for public business. None of those emails had been subjected to FOIA requests because they weren’t in the State Department’s possession. Judicial Watch’s case took on a new dimension.

The Clinton campaign, for its part, holds Judicial Watch in equal contempt as Fitton holds the candidate.

“Judicial Watch represents everything that is wrong with our political system,” Clinton campaign spokesman Nick Merrill told The Daily Beast. “Manufacturing wrongdoing has been central to their singular agenda since their inception. Worse, they do this by clogging up the courts at the expense of tens of millions of taxpayer dollars. Justice is the last thing they seek. They are only interested in headlines, and have made a complete mockery of our system.”

Fitton, Judicial Watch’s president, may have found himself in the middle of a battle royale with the most important political family in America. But this is hardly new territory for the self-described conservative activist, who has been investigating government corruption and alleged malfeasance in Washington for more than 20 years. Since its founding in 1994, his group has filed suits against every presidential administration. But in Hillary Clinton, Fitton may have found his white whale.

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The news about Clinton’s private email servers spawned dozens of lawsuits demanding emails and other documents about the unorthodox setup, which was criticized by the State Department inspector general. The Daily Beast has filed one in conjunction with the James Madison Project, another pro-transparency group, seeking information about how Clinton’s personal lawyer stored copies of the emails in his office. Those documents show that State Department officials went out of their way to accommodate Clinton and her attorneys in storing emails that were later found to contain classified information.

But the Judicial Watch lawsuit, along with one more it brought in Clinton-related matters, is different from all the others in that judges have allowed for “discovery,” the legal process by which plaintiffs can depose witnesses on-the-record and probe deeper for answers to questions.

“Getting depositions in a FOIA case is incredibly rare,” Jason Leopold, the senior investigative correspondent for Vice News and the unofficial FOIA dean among journalists, told The Daily Beast. Usually, FOIA lawsuits involve dueling legal briefs and correspondences. But the judges in Judicial Watch’s lawsuits believed that extraordinary circumstances called for different measures.

“Where there is evidence of government wrongdoing and bad faith, as here, limited discovery is appropriate, even though it is exceedingly rare in FOIA cases,” Judge Royce Lamberth, who is overseeing the second case, related to the so-called talking points U.S. officials crafted following the terrorist attacks on the U.S. consulate in Benghazi, Libya, said when he ordered discovery in March.

Leopold, who estimated that he has about 1,200 to 1,300 requests filed now on a wide range of issues concerning government affairs, brought the original lawsuit that caused the State Department to start turning over tens of thousands of Clinton’s emails in a months-long cascade. But even he hasn’t been granted the discovery process.

“That’s so important that they got discovery,” Leopold said. “Through everything that they have, they can build a mosaic in a sense to understand what was going on behind the scenes.”

That makes Judicial Watch perhaps the prickliest thorn in Clinton’s side. The depositions will stretch until the end of June, just as Clinton is gearing up for the Democratic convention in Philadelphia. They may not reveal a smoking gun. But now Judicial Watch can maintain its own drip of information, one the Clinton campaign would surely prefer to cut off and must stop from turning into a flood.

Fitton and his team of investigators and lawyers at Judicial Watch may not take Clinton down. But they will pursue her through the campaign and surely into the White House, if she is elected in November.

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Judicial Watch was founded in 1994 in large measure to ferret out records about Bill Clinton’s administration. Name a scandal—and many would say a pseudo-scandal—and Judicial Watch went after it: Travelgate, Whitewater, even the conspiracy theory that Hillary Clinton was involved in the death of White House deputy counsel Vince Foster, who killed himself in 1993. Clinton’s Republican rival, Donald Trump, has peddled the discredited narrative that Clinton played a role in Foster’s death.

The Judicial Watch of today, with Fitton at the helm, has tried to move away from such paranoid fishing expeditions, which critics say were the hallmark of the organization under its founder, Larry Klayman, a former Justice Department attorney whose litigiousness seems limitless.

If the Clintons have an Inspector Javert, it’s Klayman. “Almost everyone who was anyone in the [Clinton] administration—and almost anyone who had a grudge against Clinton and his team—became a party to a Judicial Watch lawsuit, on one side or the other,” the nonpartisan National Journal wrote in a 2002 profile.

Under Klayman, Judicial Watch became a kind of litigation factory. Some of the lawsuits managed to expose information that embarrassed government officials or shed light on closed-door dealings. But Klayman’s critics saw him more as a harasser than a truth-seeker. He has attached himself to discredited speculation about senior government officials, including President Obama. “Klayman described President Obama in a lawsuit as ‘not even a naturalized U.S. citizen and thus is in the United States illegally,’ and described Obama’s birth certificate as a fraud,” the liberal watchdog group Media Matters reported.

Klayman left Judicial Watch in 2003 to run (unsuccessfully) for the U.S. Senate in Florida. The separation was about as brutal a divorce as they come. Klayman would go on to publicly claim that Fitton “set out to hijack the group to further his own personal interests.” In 2006, Klayman sued Fitton, alleging that he “sent out false and misleading fundraising letters, misused donor money, disparaged Klayman with supporters and the media, and took other actions which increased the damage to Judicial Watch, the donors and Klayman.”

Fitton responded that the allegations were “ridiculous,” meant to distract from a quarter million dollar debt he said Klayman owed the organization, and “full of lies and distortions which Judicial Watch will address in court.”

The lawsuit is still pending, 10 years after Klayman filed it.

Fitton has backed away from the most wild-eyed claims of Clinton corruption. But he’s no less ferocious in his pursuit of any and every bit of information that will expose both the former president and potential future one for the frauds he thinks they are.

Fitton and Judicial Watch’s list of grievances with Clinton aren’t confined to her tenure as secretary of state, but that’s where the group is focusing its resources now, with a team of about 20 employees who work on the organization’s FOIA cases.

While at the State Department, Fitton says Clinton shook down wealthy political donors to give to her family’s foundation, which supports charitable organizations around the world.

He pointed to a recent Wall Street Journal report that found the Clinton Global Initiative, which is part of the foundation, “set up a financial commitment that benefited a for-profit company part-owned by people with ties to the Clintons, including a current and a former Democratic official and a close friend of former President Bill Clinton.”

Judicial Watch has also sued for documents involving a uranium deal that the State Department approved and that benefitted donors to the Clinton Foundation. The New York Times reported last year on the donations and what role they may have played in the deal’s approval.

For all Fitton’s searching, Clinton’s aides and spokespersons have said repeatedly that there’s no evidence she took actions as secretary or state to support the interests of Clinton Foundation donors.

But that hasn’t stopped Fitton from searching. He told The Daily Beast that he was struck by how many times Judicial Watch has raised issues about public corruption or ineptitude that are either ignored by the mainstream press or are covered initially and then dropped. That’s one reason Judicial Watch has decided to cut out the press, and speak directly to its own network of supporters and fellow conservative activists, including the some 400,000 individuals who Fitton says help keep the organization funded.

Asked what role major news organizations play in the group’s work, Fitton replied, “We don’t rely on them anymore. Frankly, we’re our own media outlet in some respects.”

Judicial Watch’s website is chock full of press releases, articles, document dumps, and videos that lay out its findings in minute detail.

“We do investigative journalism,” Fitton said. He called Judicial Watch’s pursuit of documents related to the 2012 terrorist attacks in Benghazi, another episode haunting Clinton’s White House bid, “the most significant non-governmental investigation in modern history.”

Such boasts will surely inspire howls of laughter and outrage in Camp Clinton, which regards the Benghazi “scandal” as a concocted one. (Clinton was at turns dismissive and defiant in October 2015 when she testified at a House hearing and rejected the notion that she somehow personally bore responsibility for the deadly attacks. “It has been rejected and disproven by non-partisan, dispassionate investigators but nevertheless having it continued to be bandied around is deeply distressing to me. I would imagine I’ve thought more about what happened than all of you put together. I’ve lost more sleep than all of you put together,” she said.)

But there’s no denying that Judicial Watch’s work has looked in some respects like investigative reporting. The group obtained the emails that showed White House aides crafting public talking points about the Benghazi attacks, which Clinton’s critics believe showed officials trying to obscure the real cause of the disaster that claimed the lives of four Americans, including U.S. ambassador Chris Stephens. And if not for those emails, Republicans in Congress might not have formed a select committee to investigate what happened in Benghazi.

Fitton was so confident, in fact, that Judicial Watch has been practicing journalism that the group submitted three entries for the most recent round of Pulitzer prizes, the most prestigious award in all of American journalism and letters. Pulitzer Prize Administrator Mike Pride told Fitton that Judicial Watch was ineligible because it’s an “advocacy site,” and that the Pulitzer committee demands entrants “practice journalism based on the highest journalistic principles.”

Fitton told Pride in an email that his characterization was “an unfounded smear. I also do not know what you mean by ‘advocacy.’ Is there any doubt about the liberal philosophy or ‘advocacy’ of prior winners Inside Climate News, the Center for Public Integrity, or ProPublica? Many other prior winners are prime examples of ‘advocacy’ journalism, as well.” The email exchange between Pride and Fitton was first reported by The Daily Caller.

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Fitton’s biography reads in some passages like that of a budding journalist. He came to Washington in the late 1980s as a self-described “conservative activist” who didn’t find a home in the GOP establishment.

“I was never a party person,” he said.

In the mid-1990s, Fitton joined the cast of a short-lived political talk show show called Youngbloods, a kind of Real World meets The McLaughlin Group that was supposed to appeal to a new generation of political junkies. The show pitted young conservatives against young liberals. Fitton, then in his mid-twenties and working for another watchdog group, Accuracy in Media, was described as the “conservative bomb thrower” of the group in a 1995 Baltimore Sun profile.

“Abolishing the [Environmental Protection Agency] would be the best thing for the environment,” he declared on one show. “I have a feeling if we didn’t have the EPA, we would find a way to take care of ourselves.”

Fitton became a regular on the talking head circuit. Even then, he was targeting Hillary Clinton. In a March 1995 C-SPAN appearance, he criticized the then-first lady for taking on a policy role in her husband’s administration by going on foreign visits.

“President Clinton decided he doesn’t have enough time to go to Pakistan. He doesn’t have enough time to go to India. He’s going to send his wife, Hillary Clinton,” Fitton said. The White House had said Clinton would be sticking to more “traditional” causes like fighting cancer and child hunger, he said, not fashioning a “new role as a foreign policy representative for the United States.”

(When Clinton declared in 1998 that a “vast right-wing conspiracy” was out to tarnish her and her husband, she could have had Fitton in mind.)

But Fitton apparently found no joy in on-air combat. Asked if he enjoyed his time on Youngbloods, a gig that most twenty-something climbers in Washington would crave, Fitton looked perplexed. “That’s not really the way I looked at it,” he said. “It was just work. I’m not much of a joker when it comes to politics.”

He’s not kidding. One could fairly describe Fitton as humorless, at least when it comes to his mission to hold public officials to account. Throughout the interview, he was visibly uncomfortable with questions about his own history and background and insisted that he preferred to focus on Judicial Watch.

Struggling to find some joyfulness in his profession, Fitton settled on this answer: “I enjoy making the right people uncomfortable.”

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Although Fitton embraces the conservative label, Judicial Watch resists easy, partisan characterization. The group sued George W. Bush’s administration twice as often as it did Bill Clinton’s, Fitton noted. Judicial Watch went after potential conflicts of interest between Vice President Dick Cheney and Halliburton, the defense contractor where he’d once been CEO and that received billions of dollars in Defense Department contracts following the U.S. invasion of Iraq. Judicial Watch also sued for documents about a White House energy task force that Cheney created. And when House Speaker John Boehner resigned from Congress last September, Fitton publicly took credit for driving him from office.

“Judicial Watch has had more success investigating the IRS, Benghazi, and Clinton email scandals than any House committee under Boehner’s direction,” Fitton said in a statement at the time, urging the House to put an end to the “elected despotism” that had prevailed under Boehner’s watch.

In Fitton’s world, hypocrisy and malevolence is bipartisan. And while he insists politics aren’t motivating him, he celebrates his work for having a political effect.

Fitton insisted that in pursuing Clinton he was not out to sink her campaign. “Our goal is to hold her accountable to the rule of law,” he replied. But it may be difficult for Fitton to persuade others that he is really motivated by a deeply held principle that Clinton should be held accountable rather than by his own political assessment that she is unfit to hold elected office, as anyone who “clearly has no respect for the rule of law” would be.

But if Clinton weren’t running for president, there’s little doubt that Fitton and Judicial Watch would find other targets. His appetite is voracious. And that should make any public official at least slightly nervous.

Asked if there was any subject that he wouldn’t pursue, any matter that he would consider too trivial for Judicial Watch to address in court, Fitton paused. “I don’t know,” he said. “On a good day, I could be convinced everything is important.”