Roger Mudd, a longtime CBS News political correspondent who reported on the Pentagon’s profligate spending, whose interview with Edward M. Kennedy ended the senator’s White House prospects and who briefly shared the anchor job at his onetime rival, NBC News, died March 9 at his home in McLean, Va. He was 93.

The cause was complications from kidney failure, said a son, Jonathan Mudd.

Mr. Mudd spent almost 20 years covering Capitol Hill, political campaigns and corruption scandals for CBS News. He did special reports on the Watergate scandal and its fallout, including the resignation of President Richard M. Nixon in 1974.

His 1979 interview of Kennedy, who represented Massachusetts, was credited with crushing the senator’s presidential ambitions just as he was preparing to challenge President Jimmy Carter for the 1980 Democratic nomination.

Kennedy awkwardly offered incomplete, rambling answers to basic questions about his family and personal life and was stopped cold when Mr. Mudd asked him directly: “Why do you want to be president?”

There was a long, awkward pause before Kennedy could say a word. When Mr. Mudd asked what distinguished him from Carter, Kennedy failed to provide substantive answers to fundamental questions, giving viewers the impression that the senator was ill-prepared for the job of commander in chief.

The interview remains one of the most devastating in political history. Kennedy — whose brother John was president and whose brother Robert was assassinated on the campaign trail — lost his bid for the nomination and never mounted a run for the presidency again.

For years, Mr. Mudd cultivated a straightforward, almost folksy manner on camera, and he was long considered the heir apparent at CBS to the venerable evening news anchor Walter Cronkite.

Mr. Mudd sat in the anchor chair on weekends and during Cronkite’s vacations, but when CBS announced Cronkite’s retirement in 1980, Mr. Mudd’s onetime Washington bureau colleague, Dan Rather, received the nod. Mr. Mudd quit the network for NBC, where he shared the anchor desk for a year with Tom Brokaw before being pushed aside in 1983.

By his own admission, Mr. Mudd’s greatest strength was not at the anchor desk, but as a reporter covering elections and the halls of Congress. New York magazine media writer Desmond Smith pronounced him “the best Washington broadcast reporter of his generation.”

Mr. Mudd joined the CBS Washington bureau in 1961 at a time when CBS was considered the premier network for news. He became nationally known for his coverage from the Capitol during a two-month filibuster of what would become the Civil Rights Act of 1964, one of the most significant pieces of civil rights legislation in history.

Beginning during a late-March snowstorm, Mr. Mudd reported day after day on the filibuster and on the senators, most of them Southern Democrats, who refused to yield the floor.

Mr. Mudd’s “continued presence at the scene of Washington inaction has personalized and dramatized the halting process of our Government to the average viewer in a way no amount of words or secondary reports could have,” New York Herald Tribune television critic John Horn wrote. “A viewer could identify with Mudd, stand on the steps with him and have brought home in a compelling way the Senate stall and sitdown against effective government by Southern Democrats.”

In 1968, Mr. Mudd covered the presidential campaign of Robert F. Kennedy and was present at the Ambassador Hotel in Los Angeles when Kennedy was assassinated in June of that year.

After the shooting, he saw Kennedy’s wife, Ethel, standing by herself. He put his arm around her waist and elbowed his way through the milling crowd, guiding her to her husband.

“She hugged me as if I were an oak tree — just something to cling to,” Mr. Mudd wrote in his 2008 memoir, “The Place to Be.” “I recall forcing some screaming, bellowing men to give way so that Ethel could reach the side of her dying husband.”

Mr. Mudd also became known at CBS as the host of in-depth investigations, which were once a common prime-time presence on the major networks. In 1971, he was the narrator and chief reporter of “The Selling of the Pentagon,” which raised questions about extravagant military spending and the Pentagon’s $30 million annual public-relations budget during the Vietnam War.

“On this broadcast, we have seen violence made glamorous,” Mr. Mudd said, “expensive weapons advertised as if they were automobiles, biased opinions presented as straight facts . . . This propaganda barrage is the creation of a runaway bureaucracy that frustrates attempts to control it.”

The broadcast was criticized by the Pentagon and hawkish politicians. A House committee called for an investigation — not of unchecked military spending but of CBS. Rep. Harley O. Staggers (D-W.Va.) issued subpoenas to the network, demanding that it turn over its raw footage and other materials related to the documentary. CBS refused. Network president Frank Stanton testified before a congressional panel and was threatened with a citation for contempt.

In the end, Congress backed down. “The Selling of the Pentagon” came to be seen as a landmark achievement in TV investigative reporting. Mr. Mudd received one of his five Emmy Awards for the program, which also won the Peabody and George Polk awards for journalism.

Among the program’s sharpest detractors was Vice President Spiro T. Agnew, who called it “a clever propaganda attempt to discredit the Defense establishment.” Mr. Mudd went on to cover Agnew’s resignation in 1973 after the vice president pleaded no contest to income tax evasion.

Roger Harrison Mudd, whose father was a cartographer and engineer, was born on Feb. 9, 1928, in Washington. The family was distantly related to Samuel A. Mudd, a Southern Maryland doctor who treated John Wilkes Booth’s broken leg after Booth assassinated Abraham Lincoln in 1865.

Mr. Mudd was a 1945 graduate of Woodrow Wilson High School in the District, then after Army service graduated in 1950 from Washington and Lee University in Lexington, Va. He received a master’s degree in history in 1953 from the University of North Carolina at Chapel Hill and began working at the Richmond News Leader newspaper and later at a radio station owned by the paper, WRNL.

His broadcasting career got off to an inauspicious start when he was reading a bulletin on the medical condition of Pope Pius XII.

“To my horror,” Mr. Mudd recounted in his memoir, “I heard myself saying, ‘The condition of Pipe Poeus has grown steadily worse and they have summoned to the Vatican bedside the Pipe’s doctor and two Swish spesulists.’ ”

Mr. Mudd came to Washington in 1956 as a radio and TV reporter for WTOP, then a CBS affiliate. Five years later, he joined the network’s Washington bureau.

Mr. Mudd admitted in his memoir that he could be “a pain in the neck and elsewhere,” sometimes angering his corporate bosses at CBS. After a 1970 speech at Washington and Lee, in which he criticized TV news as a “crude” medium that devalues thoughtful coverage, he was removed as Cronkite’s backup for two years.

In 1980, when Rather was named Cronkite’s successor as anchor of the “CBS Evening News,” the move was seen as a slight to Mr. Mudd. He left the network for NBC, where his contract promised him the top job at “NBC Nightly News,” if then-anchor John Chancellor should step down.

But to keep rising star Tom Brokaw from jumping to another network, Mr. Mudd waived the clause in his contract that called for him to become NBC’s sole anchor. In an awkward succession, Chancellor stepped down in 1982 to do commentary for the network, while Brokaw and Mr. Mudd became joint anchors of the “Nightly News.”

The arrangement pleased no one, least of all the viewers. The “Nightly News” was languishing in third place among the three legacy networks when Mr. Mudd was eased out of the anchor seat after a year to return to reporting.

The anchor position was “among the most boring jobs in television news,” he later wrote, and little more than “hood ornaments for their companies.”

In 1987, after NBC bought out Mr. Mudd’s contract for a reported $3 million, he became a correspondent for the “MacNeil-Lehrer NewsHour” on PBS, then worked as a host on the History Channel from 1995 to 2004.

In 2010, Mr. Mudd donated $4 million to Washington and Lee to endow a center for ethics that bears his name.

He and his wife of 53 years, the former Emma Jeanne “E.J.” Spears, lived for decades in McLean. She died in 2011. Survivors include four children, Daniel Mudd of Greenwich, Conn., Maria Mudd Ruth of Olympia, Wash., Jonathan Mudd of Washington and Matthew Mudd of McLean; 14 grandchildren; and two great-grandchildren.

Mr. Mudd’s memoir was widely praised as an unvarnished look inside TV news and politics. His 20 years in the CBS Washington bureau, he wrote, were the high point of his professional life.

“Even during the six years I spent at NBC, trying my best to beat CBS,” he wrote, “there was always a little hitch, perhaps a slight choke, in saying, ‘I’m Roger Mudd, NBC News, Washington.’

“I had never truly ceased being a CBS man.”

An earlier version of this story incorrectly stated that Roger Mudd graduated from Woodrow Wilson High School in Washington in 1946.