Ben J. Wattenberg, a writer, television commentator and self-described “old center-right Democrat” who defied easy political categorizations during nearly five decades as a public intellectual, died June 28 at a hospital in Washington. He was 81.

The cause was complications from surgery, said his son, Daniel Wattenberg. Mr. Wattenberg had written a syndicated newspaper column, was a senior fellow at the American Enterprise Institute and was known to public-television viewers as host of programs including “Think Tank with Ben Wattenberg.”

For the past half-century, Mr. Wattenberg was an almost constant presence in public discussion of American politics, governance and society. He frequently was identified as a neoconservative and stood out in a political landscape that grew increasingly polarized between right and left.

“I am a paleoliberal, a supply-side infrastructuralist, a neomanifest destinarian, a numbers nut, a pro-natalist redistributionist capitalist,” he once wrote — “and still a hawk.”

Mr. Wattenberg became widely known for his argument that, even amid social upheaval and economic difficulty, the United States was scarcely as troubled as the media and many liberals suggested. He captured his worldview in the title of one of his books, “The Good News Is the Bad News Is Wrong” (1984).

Mr. Wattenbeg defied easy political categorizations during five decades as a public intellectual. (Courtesy Think Tank)

Mr. Wattenberg first drew attention in 1965 with the publication of the volume “This U.S.A.: An Unexpected Family Portrait of 194,067,296 Americans Drawn From the Census.” He and his co-author, Richard M. Scammon, director of the Census Bureau, marhsalled evidence from the 1960 Census to show that “the United States is entering a Golden Age, that we have achieved a better America.”

The book cited decreases in the rates of divorce, traffic deaths and school dropouts. Certain drug addictions were on the decline and illiteracy was disappearing. Among African Americans, the authors found greater economic and educational opportunity than was widely believed to exist.

“It is time to call upon the carpet masters of the semantic fuzz, and the purveyors of the obfuscating, sophisticated phrase,” wrote the authors, as quoted in a profile of Mr. Wattenberg published earlier this year in National Affairs. “It is time to investigate the capital-lettered afflictions that seem to issue from every typewriter throughout the land, spreading apparent doom on an otherwise healthy society.”

Critics accused the authors of being excessively boosterish when U.S. society was divided by issues such as the civil rights movement and the Vietnam War. The book nonetheless attracted the attention of then-President Lyndon B. Johnson and Vice President Hubert H. Humphrey.

Mr. Wattenberg was invited to the White House where Johnson met with him, reportedly while wearing blue pajamas. Mr. Wattenberg became a White House speechwriter for Johnson and later an adviser to Humphrey on his unsuccessful 1968 presidential campaign and winning 1970 Senate race in Minnesota.

In 1970, Mr. Wattenberg attracted even broader notice with the publication of “The Real Majority,” a bestseller also written with Scammon. The book drew on polls and surveys to present a portrait of an average American voter who was “middle aged, middle class and middle minded,” as well as “unyoung, unpoor and unblack.” It advised the Democratic Party to move from left to center and to focus on law-and-order issues rather than on more progressive causes.

In 1972, Sen. George S. McGovern of South Dakota, who embodied the party’s left wing, received the Democratic nomination for president and lost to incumbent Republican Richard M. Nixon in a 49-state landslide. Mr. Wattenberg worked that year and in 1976 — when Democrat Jimmy Carter won the White House — for Democratic Sen. Henry M. “Scoop” Jackson of Washington, who combined progressive social positions with conservative views on defense.

Mr. Wattenberg sought to cultivate Democratic centrists by helping found the Coalition for a Democratic Majority, a neoconservative group within the party. Writing with Scammon, he encapsulated his frustration at more liberal colleagues with an ironic paraphrase of their argument: “Our programs have failed. Let us continue.”

Mr. Wattenberg drew the attention of President Bill Clinton with the book “Values Matter Most” (1995), in which he argued that the president and the Democratic Party had helped bring about the Republican congressional victories of 1994 by backing off the centrist themes on which Clinton had won the White House. Clinton phoned Mr. Wattenberg and, by the author’s account, said he agreed with the assessment of his administration's shortcomings.

Joseph Ben Zion Wattenberg, a son of Jewish immigrants from what was then the British mandate of Palestine, was born in New York on Aug. 26, 1933. He was a brother of actress Rebecca Schull, best known for her role as the flighty Fay on the sitcom “Wings.”

Mr. Wattenberg received a bachelor’s degree in 1955 from Hobart College in Geneva, N.Y., before serving in the Air Force. He began his writing career as a marine expert, editing trade journals and penning a book for young readers about harbors.

Later in his career, Mr. Wattenberg was appointed by presidents of both parties to governmental bodies that included the Board for International Broadcasting. He hosted TV programs including “In Search of the Real America” and “Ben Wattenberg At Large.”

His books included “The Birth Dearth” (1987), about the long-term dangers of a low societal birthrate. His last published book was “Fighting Words: A Tale of How Liberals Created Neo-Conservatism” (2008). Mr. Wattenberg also wrote a novel, “Against All Enemies” (1977), co-authored with Ervin S. Duggan.

Mr. Wattenberg’s marriages to Marna Hade and Diane Abelman ended in divorce.

Besides his sister, survivors include three children from his first marriage, Ruth Wattenberg, Daniel Wattenberg and Sarah Wattenberg, all of Washington; a daughter from his second marriage, Rachel Wattenberg of Washington; and four grandchildren.

During a career in which Mr. Wattenberg often presented a rosy view of the trajectory of the United States, some critics called him Panglossian. But he said the country had a long record supporting his beliefs.

“In American history,” Mr. Wattenberg once wrote, “the evidence suggests that it is the optimist who has been the realist.”