In his opening remarks at the House Select Committee on Benghazi, Rep. Elijah Cummings (D-Md.) said Chairman Trey Gowdy (R-S.C.) was wrong when he said it was "impossible to conduct a serious fact-centric investigation" of the Sept. 11 attack in Benghazi, Libya. (AP)

As she strode through the grand double doors leading to the Thursday hearing by the House Select Committee on Benghazi, the first hand that Hillary Rodham Clinton shook belonged to Rep. Elijah Cummings, the committee’s highest-ranking Democrat and her most vociferous ally on the panel.

Minutes later, Cummings (D-Md.) delivered an unbridled attack on the Republican-led committee’s investigation, which he described as an “abusive effort” to “derail Secretary Clinton’s presidential campaign.”

“It is time, and it is time now,” Cummings bellowed, his rich baritone filling the crowded, high-ceilinged hearing room, “for the Republicans to end this taxpayer-funded fishing expedition.”

The Benghazi hearing was official Washington at its histrionic best, thick with jostling scrums of reporters and photographers, Republicans and Democrats hurling rhetorical daggers, and one very well-known presidential candidate and her entourage making a dramatic entrance.

Yet, it was also a chance for Cummings to command the national stage and defend his party’s leading Democrat at a moment when he is openly considering a campaign for the U.S. Senate seat that Barbara A. Mikulski (D-Md.) will vacate when she retires next year.

Here are top moments from the House Select Committee hearing on Benghazi where former secretary of state Hillary Clinton testified. (Sarah Parnass/The Washington Post)

The 11-term congressman did not wait long to make an impression, clashing with the committee’s chairman, Rep. Trey Gowdy (R-S.C.), and assailing Republicans.

Gowdy began the hearing with an opening statement in which he repeated the word “truth” no less than 21 times as he described the committee’s mission.

Taking the microphone when Gowdy was done, Cummings intoned: “Truth, the whole truth and nothing but the truth.”

He then repeated the words, establishing a motif he would return to later.

Cummings is well known in his congressional district, which includes Baltimore and its adjoining suburbs, and his statewide strength was evident in a recent Washington Post poll that showed him with a double-digit lead over Rep. Chris Van Hollen (Montgomery) and Rep. Donna F. Edwards (Prince George’s), two Democrats who have declared their candidacies.

Six months ago, Cummings captured national attention in the aftermath of rioting in Baltimore as he walked the streets, urging crowds to comply with a curfew and return home — a quest that was captured nightly by swarms of television crews.

“Most Democrats already know Elijah Cummings,” said Donald Norris, the director of the school of public policy at the University of Maryland Baltimore County. Referring to the Benghazi hearing, he said, “This is like free advertising, and it keeps his name out there in front of everyone.”

Yet whether Cummings decides to run is far from certain. Even as he has said publicly that he is considering a campaign, friends and associates said that Cummings has indicated that he plans to remain in the House.

The Rev. Jamal Bryant, who declared in September his candidacy for Cummings’s House seat, said he then decided not to run after speaking with the congressman. “He said he was staying in the 7th District,” Bryant recalled. “He felt he could do the greater work in the 7th, with the seniority he had, rather than starting fresh anew.”

Maryland Senate President Thomas V. “Mike” Miller Jr. (D-Calvert), who served with Cummings in Annapolis, said his sense from speaking with the congressman several weeks ago was that he would remain in the House.

One reason, Miller said, was that Cummings, who is black, did not want to split votes with Edwards, who also is black. “He did not want to be the one to adversely effect Donna’s chances,” Miller said. “He’s thrilled with the role he plays. He’s on ‘Face the Nation.’ He’s the ranking member on the Benghazi committee.”

Yet, Miller also said that the recent poll numbers could be enough to shift Cummings’s thinking. “You see polling that says you could be a United States senator?” Miller said. “You owe it to the state of Maryland, you owe it to your constituents to give it careful consideration.”

Cummings told The Post this month that he would wait until after Clinton’s Benghazi testimony to announce his decision because he did not want to be viewed as using the committee to advance politically.

At Thursday’s hearing, Cummings went out of his way to repeat that he did not view himself as a partisan warrior. At the same time, he was quick to insist that the investigation was a Republican political ploy and reminded his audience that four GOP presidential candidates have cited Benghazi to attack Clinton.

At one point, as Gowdy bore down on Clinton about e-mails she received from her longtime friend Sidney Blumenthal, Cummings interrupted and said: “Gentleman, yield! Gentleman, yield! You have made several inaccurate statements.”

Moments later, after Gowdy called a recess, Cummings stepped before a clot of reporters in the hallway and said his purpose was not to “defend Hillary Clinton.”

His purpose, he said, is “the truth, the whole truth and nothing but the truth.”

“Let the world see it!” he said, before disappearing behind a shut door.