Mr. Helms’s former chief of staff, James W.C. Broughton, said that the senator died at the Mayview Convalescent Center in Raleigh, where he had lived for the last several years. Mr. Helms had been in “a period of declining health” recently, Mr. Broughton said.

In a 52-year political career that ended with his retirement from the Senate in 2002, Mr. Helms became a beacon for the right wing of American politics, a lightning rod for the left, and, often, a mighty pain for Presidents whatever their political leaning.

Ronald Reagan, a friend who could thank Mr. Helms for critical campaign help, once described him as a “thorn in my side.” Mr. Helms was known for taking on anyone, even leaders of his own party, who strayed from his idea of ideological purity.

“I didn’t come to Washington to be a yes man for any President, Democrat or Republican,” he said in an interview in 1989. “I didn’t come to Washington to get along and win any popularity contests.”

Perhaps his most visible accomplishments in the Senate came two decades apart. One was a 1996 measure that tightened trade sanctions against the Marxist government of Fidel Castro in Cuba. The other, a 1973 amendment to the Foreign Assistance Act, prevented American money from going to international family planning organizations that, in his words, “provide or promote” abortion. He also introduced amendments to reduce or eliminate funds for foreign aid, welfare programs and the arts.

David A. Keene, chairman of the American Conservative Union, said recently that Mr. Helms’s contribution to the conservative movement was “incredibly important.”

For one thing, he said, Mr. Helms was alert to technological change, especially the importance of direct mail, and readily signed fund-raising letters that helped conservative organizations get started.

Mr. Helms was also instrumental in keeping Mr. Reagan’s presidential campaign alive in 1976 when it was broke and limping after a series of defeats in the Republican primaries.

And in the Senate, Mr. Keene said, Mr. Helms was a rallying point for conservatives. As chairman of the Foreign Relations Committee, he supported Mr. Reagan on issues like aid to the Nicaraguan Contras. “Without Jesse, it would have been hard for Reagan to hold the line,” he said.

Mr. Helms saw himself as a simple man — he even used the word “redneck” to describe himself — protecting simple American values from the onslaught of permissiveness, foreign influence and moral relativism. For 30 years he cut a familiar figure on the Senate floor, typically wearing horn-rimmed glasses, black wing tip shoes and, on the lapels of his gray suits, American flag and Free Masonry pins.

He liked his art uncomplicated.

“The self-proclaimed, self-anointed art experts would scoff and say, ‘Oooh, terrible,’ but I like beautiful things, not modern art,” he told The New York Times in 1989, during a pitched battle over federal subsidies to the arts. “I can’t even figure out that sculpture in the Hart Building.” He was referring to an Alexander Calder mobile.

In the 1980’s he took on the National Endowment for the Arts for subsidizing art that he found offensive, chiefly that of the photographer Robert Mapplethorpe, who explored gay themes in some of his work, and of the artist Andres Serrano, who depicted a crucifix submerged in urine. He later led an ill-fated attempt to take over CBS, exhorting conservatives to buy up stock in order to stop what he saw as a liberal bias in its news reporting.

He was also well known for holding up votes on treaties and appointments to win a point. His willingness to block the business of the Senate or the will of Presidents earned him the sobriquet “Senator No” — a label he relished.

In campaigns and in the Senate, Mr. Helms stood out in both his words and his tactics.

He fought bitterly against Federal aid for AIDS research and treatment, saying the disease resulted from “unnatural” and “disgusting” homosexual behavior.

“Nothing positive happened to Sodom and Gomorrah,” he said, “and nothing positive is likely to happen to America if our people succumb to the drumbeats of support for the homosexual lifestyle.”

In his last year in the Senate, he decided to support AIDS measures in Africa, where heterosexual transmission of the disease is most common.

Trailing in a tough re-election fight in 1990 against a black opponent, Harvey Gantt, the former mayor of Charlotte, Mr. Helms unveiled a nakedly racial campaign ad in which a pair of hands belonging to a white job-seeker crumpled a rejection slip as an announcer explained that the job had been given to an unqualified member of a minority. Mr. Helms went on to victory.

In 1994, angered at President Clinton, Mr. Helms suggested in print that if Mr. Clinton was to visit North Carolina, “He’d better bring a bodyguard.” He later said the remark had been “a mistake.”

His bruising style and right-wing politics won him many friends in his home state and across the nation, but he also created a legion of enemies. Millions of dollars were raised outside North Carolina both from those who flocked to his ideological banner and from those who ached to see him defeated. He never won more than 55 percent of the vote in five campaigns for the Senate.

“He was a very polarizing politician,” said Ferrell Guillory, a veteran North Carolina journalist. “He was not a consensus builder. He didn’t want everybody to vote for him. He just wanted enough.”

But as tough as he could be in the political theater, Mr. Helms could exhibit a softer, warmer, even impish side in his personal dealings, even with political adversaries.

In 1963, after 21 years of marriage, Mr. Helms and his wife, Dorothy, adopted a disabled child, Charles, after they read a newspaper article in which the child, who was nine at the time, plaintively said that he wanted a mother and father for Christmas.

Claude Sitton, the editor of The Raleigh News and Observer, a newspaper whose coverage and editorials gave Mr. Helms fits, was startled when Mr. Helms sent him a gift at his retirement party. It was a fine bay horse. “This is Jesse,” said a sign hung around the horse’s neck. “You been riding Jesse for years. Don’t stop now.”

He welcomed teen-agers. Even when lobbyists could not get in to see him, high school students could. His office once calculated that he had met with 170,000 teen-agers in his 30 years in the Senate.

Jesse Alexander Helms Jr. was born to Jesse Sr. and Ethel Mae Helms on Oct. 18, 1921 in Monroe, N.C., where his father was the chief of police. A hamlet in the North Carolina Piedmont, Monroe embodied the kind of small-town virtue that he would vigorously promote throughout his career. “Everybody understood everybody else,” he said of his hometown. “Everybody understood that it was important not to do certain things, and that, if you did them, you would pay for it.”

For Mr. Helms, the orderliness of the small town even encompassed racial segregation; as a child, he saw it not as a great evil but as an accepted part of his world. Mr. Helms always insisted that journalism had been his first choice for a career. He quit Wake Forest College before he graduated to become a reporter for The Raleigh Times. In 1942, he married the former Dorothy Coble, of Raleigh, whom he had met at Wake Forest. They went on to have three children.

He is survived by his wife, Dorothy, and three children, Jane Helms Knox of Raleigh; Nancy Helms Grigg of Chapel Hill, and Charles Helms, of Winston-Salem, N.C. He is also survived by seven grandchildren and one great-grandchild.

After serving in the Navy in World War II, Mr. Helms became news and program director at WRAL, a radio station in Raleigh, from 1948 to 1951. It was at WRAL that he cut his political teeth, covering the 1950 race for the Senate between Frank Porter Graham, the former President of the University of North Carolina, and Willis Smith, the former Speaker of the North Carolina House. The race was nasty. At one point, Willis supporters passed out handbills bearing a doctored photograph depicting Mr. Graham’s wife dancing with a black man.

Though his station covered the campaign, Mr. Helms also served as an unofficial adviser to the Willis campaign. He denied having anything to do with the handbills, or that they were even printed by the campaign. Mr. Willis won, and Mr. Helms went with him to Washington to work in his Senatorial office.

In 1953, however, he left Washington to become the chairman of the North Carolina Bankers Association. Four years later he was elected to the Raleigh City Council and served on it until 1961.

From 1960 to 1972 he did political commentary on WRAL radio, WRAL-TV and the Tobacco Radio Network. The stations’ statewide reach and Mr. Helms’s piquant commentaries against communism, the “lax” criminal justice system and welfare turned Mr. Helms into a household name, both loved and hated.

“Look carefully into the faces of the people participating,” he said in a 1968 editorial against anti-Vietnam war protests. “What you will see, for the most part, are dirty, unshaven, often crude young men and stringy-haired awkward young women who cannot attract attention any other way.”

In 1970 he switched his party registration to Republican from Democrat. Two years later, he upset the favorite by a convincing 120,000 votes to win a Senate seat.

The first few years as a Senator were difficult for Mr. Helms. He was overshadowed by the state’s better-known Senator, Sam Ervin. His conservative idol, President Richard M. Nixon, was driven from office by the Watergate scandal, and his vote against Nelson Rockefeller, President Ford’s choice for vice president, alienated him from the party’s leadership. He was in debt. He considered retiring after his first term, but changed his mind.

“I looked around the Senate and thought that it needed conservative votes and that it didn’t have too many,” he said.

Mr. Helms’s political longevity and his national stature were enhanced when he and his close political adviser, Tom Ellis, a North Carolina lawyer, started the North Carolina Congressional Club. Originally formed to help pay off Mr. Helms’s campaign debts from the 1972 campaign, the club, which later changed its name to the National Congressional Club, grew to be a political action committee and the centerpiece of a multimillion-dollar set of nonprofit corporations, tax-exempt foundations and political education committees. Compiling nationwide lists of donors, they raised money and dispersed it to support conservative causes.

The effort, in Mr. Ellis’s view, was necessary to counter the influence of the huge liberal-oriented foundations that dominated national politics at the time. But the effort also turned Mr. Helms into a national figure, with a power base outside the Republican party and with the ability to get his message out without having to rely on what he considered the liberal national news media.

Mr. Helms also showed his political power in 1976, when he threw his weight and political organization behind Mr. Reagan’s campaign for the Republican presidential nomination. Mr. Reagan had lost a string of primaries to the incumbent, Gerald R. Ford, and it was believed that if the President defeated him in North Carolina, Mr. Reagan’s bid, and perhaps his political career, would end.