Why is it so hard to understand for some people…

Rep. Trey Gowdy is a man under fierce pressure as he leads a congressional Benghazi investigation that’s dismissed by Democrats as partisan and even questioned by some fellow Republicans.

No matter.

The former prosecutor and three-term South Carolina Republican known for his “Southern politeness” is pressing ahead, determined to get the facts about the long night of Sept. 11, 2012, when extremists hit two U.S. facilities in Benghazi, Libya, and killed four Americans, including Ambassador Chris Stevens.

On Thursday, as chairman of the House Select Committee on Benghazi, Gowdy faces the star witness in the 17-month, Republican-led investigation that already has surpassed the 1970s-era Watergate probe in length. Hillary Rodham Clinton, secretary of state when the attack happened and now a Democratic presidential candidate, will testify in the highly anticipated hearing on Capitol Hill.

For all the talk of how Clinton used a private email server as secretary, Gowdy pledged in a recent interview that the hearing will be “Benghazi-centric,” focused on security before and during the attacks. Some questions are likely on Clinton’s use of a private email account and server for government business, Gowdy said, but he maintains that his approach may “shock you with fairness.”

Clinton has said the use of a private server was a mistake.

The 51-year-old Gowdy, boyish-looking with close-cropped silver hair, has cast himself as a fact-finder as he deals with Republicans eager to portray the attacks as a major national security failure of the Obama administration and Democrats who call the inquiry a pointless partisan exercise after some seven other investigations into the raids.

Gowdy has conducted most of the committee’s work behind closed doors while holding just three public hearings in 17 months, the last one in January. The panel has interviewed more than 50 witnesses— including seven eyewitnesses whom Gowdy says were never questioned by other congressional committees — and reviewed thousands of documents about security lapses, the military response and the administration’s initial, inaccurate accounts of why the attacks occurred.

House Speaker John Boehner, the driving force behind creation of the committee in May 2014, said he chose Gowdy, a member of the 2010 tea party class, because “he is one of the most professional, capable and respected members of Congress.”

“Time and time again, Trey has proven that he is the best person to ensure the American people know the truth about what happened in Benghazi,” Boehner, R-Ohio, told The Associated Press in a statement.

Democrats counter that the $4.5 million inquiry is a costly partisan hunt to destroy Clinton’s White House bid and complain that they have been frozen out of some of the committee interviews. They point to the recent comments of two Republicans who suggested Clinton is the panel’s target.

House Majority Leader Kevin McCarthy, R-Calif., said last month that the committee can take credit for Clinton’s diminished public standing in recent months, a comment he later retracted. On Wednesday, Rep. Richard Hanna, R-N.Y., who is not on the committee, said “a big part” of the Benghazi investigation was designed to go after Clinton.