Jack Anderson, 81 and ailing with Parkinson’s disease, quietly gave up his syndicated column last week after more than half a century. It was not the ending some of Richard Nixon’s men once had in mind.

In 1972, in one of the most bizarre and overlooked chapters in American political history, Anderson was the target of a Mafia-style hit ordered in the White House itself. Two Nixon operatives admitted under oath that they plotted to poison the troublemaking investigative reporter at the behest of a top aide to President Nixon. Ultimately the plot was aborted and the conspirators were arrested a few weeks later, as part of the Watergate break-in.

Anderson’s retirement symbolizes the end of an era that predates Watergate. He was the last of the old-fashioned muckrakers. In his heyday, from the 1950s through the ’70s, his daily “Washington Merry-Go-Round” column was the most widely read in the nation, reaching an audience of 40 million in nearly a thousand newspapers. Anderson’s dramatic exposes of political scandal led to resignations and prison terms. He swiped secret documents, used bugging equipment to eavesdrop on conversations, and jubilantly savaged his enemies, unconcerned with such journalistic niceties as fairness and balance.

Anderson was an important figure in the evolution of adversarial journalism, a link in the historical chain between the advocacy of Progressive-era reformers from the early 1900s and the more professionalized class of investigative reporters who came to dominate Washington in the 1970s. After World War II, when he joined the column under the late Drew Pearson, Anderson was for years the only Washington reporter of genuine influence who consistently exposed wrongdoing in the nation’s capital — from the fur-coat scandals involving presidents Truman and Eisenhower, to corruption by numerous members of Congress, to the secret foreign policy machinations of the Nixon and Reagan administrations.

Anderson was able to break these stories in part because he was an independent journalistic entrepreneur, empowered by the technology and economic autonomy of the syndicated column.

He was a strict Mormon who viewed investigative reporting as a noble calling from God. He provided a vital check on governmental power during a time when journalists preferred to socialize with public officials rather than investigate them.

To be sure, his flaws could be glaring. He was bombastic and self-righteous, even when retracting stories, such as his false report that a Democratic vice presidential nominee had been arrested for drunken driving. The muckraker’s unsavory techniques included threats, rifling through garbage, and financial relationships with sources. He openly lobbied senators on their votes, ghostwriting their speeches and using his column as leverage to influence them. His cliche-ridden evangelical style was an anachronism that sacrificed complex truths for simplistic but dramatic portrayals of good guys vs. bad.

In this respect, too, Anderson was ahead of his time, anticipating the victims-and-villains entertainment values that have come to dominate 21st-century television news. Ironically, despite the black-and-white view he expressed in his column, Anderson’s own reporting was itself a far more grayish mix of courageous digging and sensationalistic self-promotion. He embodied the contradictions that have characterized investigative reporting throughout American history; from the beginning it has alternated between the highbrow ideals of public service and the lowbrow reality of celebrity gossip.

Part circus huckster, part guerrilla fighter, part righteous rogue, Anderson waged a one-man journalistic resistance when it was exceedingly unpopular to do so. That no one has emerged to take his place shows not only the void he leaves behind but also how much America’s media landscape has changed.

Mark Feldstein, director of the journalism program at George Washington University’s school of media and public affairs, is writing a biography of Jack Anderson.