WASHINGTON - (Reuters) - U.S. Representative Elijah Cummings, a civil rights champion who over the last quarter century became one of the most influential Democrats in Congress and a key figure in the impeachment inquiry into President Donald Trump, died on Thursday. He was 68.

A powerful speaker with a formidable presence, Cummings had clashed with Trump on subjects ranging from congressional oversight of the White House to Trump’s attacks on Cummings’ native city of Baltimore, which the president called “rat-infested.”

Cummings responded in a speech early in August at the National Press Club, saying that high-level government officials should “stop invoking fear, using racist language and encouraging reprehensible behavior.”

Cummings died of “complications concerning longstanding health challenges,” his office said in a statement. He had been absent recently from Congress, to which he was first elected in 1996.

The barrel-chested Cummings was the son of African-American sharecroppers. He rose to lead the powerful House Oversight and Reform Committee, one of three congressional panels leading an impeachment inquiry that was launched on Sept. 24, after Trump asked Ukraine to investigate 2020 Democratic presidential rival Joe Biden. The panel has been involved in fights with the Trump administration over subpoenas challenged by the president.

In a time of particularly bitter partisan divide in Washington, top Democrats and Republicans alike voiced praise for Cummings on Thursday.

Senate Majority Leader Mitch McConnell, a Republican, said flags would be lowered to half-staff at the Capitol building to mark his death.

“In the House, Elijah was our North Star. He was a leader of towering character and integrity, whose stirring voice and steadfast values pushed the Congress and country to rise always to a higher purpose,” House Speaker Nancy Pelosi said in a statement.

She recalled that earlier this year, Cummings said: “When we’re dancing with the angels, the question will be asked: In 2019, what did we do to make sure we kept our democracy intact?”

Republican Representative Mark Meadows, one of the most conservative members of the House, said on Twitter of his Oversight Committee colleague: “There was no stronger advocate and no better friend than Elijah Cummings.”

Cummings told the Washington Post earlier this year that he considered Meadows a good friend, even though they disagreed on almost all issues.

Former President Barack Obama called Cummings “steely but compassionate” and said he “showed us all not only the importance of checks and balances within our democracy, but also the necessity of good people stewarding it.”

DISTRICT DEFENDER

Cummings was a trial lawyer before being elected to office to represent Baltimore and other parts of central Maryland. He graduated from Howard University and the University of Maryland School of Law.

He spent 14 years in the state legislature, becoming the first African-American to be named state House Speaker Pro Tempore, who presides over the chamber when the Speaker is absent.

When he moved to Congress, he succeeded Kweisi Mfume, who went on to lead the NAACP civil rights group.

Cummings’ standing with his constituents was clear during the 2015 riots in Baltimore after Freddie Gray, an unarmed black man, was killed when police gave him a “rough ride” in the back of a van after arresting him.

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Following a night of arson and violence, Cummings served as a calming presence in the streets, mingling with people and listening to their anger.

“When you see the destruction, you’ve also got to realize there’s pain, there’s pain behind a lot of this,” Cummings said near a drug store that was burned during the rioting.

This year, Cummings harshly criticized Trump's immigration policy and gave a tongue-lashing to U.S. Department of Homeland Security here officials over conditions for migrants detained along the southern border.

“None of us would have our children in that position,” Cummings thundered in July, accusing the administration of erecting “child internment camps.”

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Cummings said he had “no doubt” the president was a racist, after Trump attacked four minority congresswomen on Twitter.

He told the Baltimore Sun that he didn’t think Trump understood “what it feels like to be treated like less than a dog,” recalling white mobs that threw rocks and bottles at Cummings and other African-Americans seeking to integrate a swimming pool in Baltimore decades ago.

Trump then lashed out at Cummings on Twitter, calling the Congressman a “brutal bully” who represented a “disgusting, rat and rodent infested” district.

Despite their differences, Trump issued condolences to Cummings’ family and friends on Thursday.

“I got to see first hand the strength, passion and wisdom of this highly respected political leader. His work and voice on so many fronts will be very hard, if not impossible, to replace!” Trump said on Twitter.

MULTIPLE PROBES OF TRUMP ADMINISTRATION

Cummings had served as oversight chairman since January after the Democrats gained control of the House of Representatives in 2018 elections, and he plunged into multiple investigations of Trump’s personal finances and possible abuses at federal agencies.

Before the impeachment inquiry was officially launched at the end of September, Cummings’ committee was investigating whether Trump had used his office to enrich himself, his family or his businesses including Trump hotels.

Representative Carolyn Maloney will be the committee’s acting chair until a permanent one is chosen, a senior Democratic leadership aide said, adding that “the caucus process to elect a permanent chair will be announced at a later time.”

Last year, when Cummings was off work for a lengthy period due to knee problems, Maloney and another Democrat, Gerald Connolly, shared the duties of running the oversight panel.

Maryland Governor Larry Hogan has 10 days to lay out a schedule for holding special primary and general elections to replace Cummings, a process that could take until early next year to unfold. The district, with a majority African-American population, is expected to stay in Democratic hands.

Fellow Democrats noted the large void left by Cummings’ passing, and the outsized role he played.

“Today we have lost a giant,” U.S. House Majority Whip James Clyburn said.

Cummings “spoke truth to power,” said the chairman of the House Democratic Caucus, Hakeem Jeffries.