CHRISTOPHER J. Dodd is the brash senator from Connecticut who has dated Bianca Jagger, instigated a 4 a.m. doughnut fight, fought with Sen. Jesse Helms--and delivered the Democratic rebuttal to Ronald Reagan's Central America speech, suggesting the president was condoning Salvadoran security guards who, he said, murder people "gangland-style--the victim on bended knee, thumbs wired behind the back, a bullet through the brain." Some in the Connecticut senator's own party were angry he'd done it, saying he'd politicized foreign policy, but his speech made the kind of splash that a young, ambitious senator dreams of--not least because he, like most of them, thinks that someday he might like to be president. Or vice president. Speculation that he could be a running mate in 1984, however improbable, has already started.

Christopher J. Dodd is also his father's son.

Thomas J. Dodd was the senator from Connecticut whose career was ruined in 1967 when his colleagues censured him for diverting political contributions to his personal use. There were nine days of debate, then a roll call. Only four voted with him.

When Thomas Dodd finally spoke, his voice cracked, and there were tears in his eyes. "I think a terrible mistake has been made," he told a hushed Senate chamber. "And I'm the one who has to bear the scars of that for the rest of my life." Four years later, he was dead at 64.

Christopher Dodd's story is the story of a Connecticut political family, a melodrama with a good measure of Irish Catholic guilt, pathos and furor. It is a story about a son who worships a father, but who has spent the last nine years coming out from his shadow--one cast by a man who, despite his troubles and his death, is still a presence back home. Dodd says he was just "Tom Dodd's kid" when he came to the House in 1974, but in nearly a decade of old-fashioned politicking he has emerged as one of the party's young stars. In that decade, his marriage broke up, and he made a political enemy of a one-time ally. He likes the company of women, and has spent long, raucous nights in the bars of Washington and Martha's Vineyard with friends like Pat Caddell, Jimmy Carter's former pollster. Another politician might be more private about his life, but Christopher Dodd, 39, comes to the profession with an odd sense of fate.

"The lesson my father taught me," he says, "is that the issue isn't if you or I or anyone else ends up on their hindquarters. It's when. Something's going to happen, somewhere. I'm going to say something that will antagonize my constituency, and they'll want my head. And how are you going to handle it?" His words come fast, and his voice is oddly upbeat. "There's nothing sadder than a guy who gets defeated or goes through a tough period in his life, and then all of a sudden discovers, 'Golly, I thought those people were friends.' And you find yourself alone. In a sense, I know that's going to happen some day. So I'd rather decide when I want to get out. I'd like to think that the time will come when I could walk away. Because of my father. I don't want to end up like that . . . I like to win, and I'm competitive, but I'm not politically driven. Or consumed by it."

Hardly anyone he knows believes him when he says that. "It's in his veins," says his older brother Tom. In fact, friends say it's because of his father that he could never walk away. In his office, staring straight at him, hangs an oil painting of the elder Dodd that makes him look saintly. "I swear those eyes move," Dodd laughs. He has his father's watch fob, his Senate chair and his desk. "Chris really cleaned out the attic for this one," one of his sisters said when she saw the office. When he first decided to run for Congress in 1974, some of Dodd's five siblings wouldn't speak to him. "Why are you going through all this again?" he remembers they asked. "Are you trying to rewrite it?"

Dodd was in the Dominican Republic with the Peace Corps the day his father was censured. The rest of the family lived through it, but Dodd read about it two days later in a Spanish newspaper. He says he felt guilty he wasn't there, but he must have felt some relief, too. "It's not overwhelming to him," says his brother Tom. "That makes a difference." Still, Christopher Dodd can tell you exactly who voted against his father that day. Even before that, when the newspaper stories about his father's political contribution problems had started, the faculty of Thomas Dodd's alma mater, Providence College, disinvited him from speaking at the 1966 commencement. Thomas Dodd was devastated, but Christopher Dodd, who was in that year's graduating class, was enraged. He walked out, and didn't set foot on the campus again for 17 years. A few months ago, when he was asked to speak at this year's commencement, Dodd said yes--provided that the college president say a few words in honor of his father. He did.

Dodd says now that his father "didn't separate and distinguish his political and his personal life." The elder Dodd had used $116,000 in political contributions to pay personal bills; he claimed he was badly in debt at the time, and needed the money for his family. "I know that an awful lot of people feel as though what I'm doing is trying to vindicate him," Dodd says, talking over dinner after a long day of speeches in Connecticut. "But I feel no necessity for that. I literally don't have a day go by in the state, and haven't in 10 years, when somebody, sometime during the day, doesn't come up to me and say, 'You know, I knew your dad and he was a wonderful friend,' or 'He was a great fighter.' How many children go around and have people say that about their parents? Every day. Every day. I love it! Absolutely love it!"

He continues, growing more intense as he talks of his father. And then something odd happens: He contradicts what he has said moments earlier about vindication. "Russell Long once said to me, and he was a great friend of my dad's, 'I'd love to introduce a resolution that exonerates your daddy.' And I said, 'Russell, you don't have to. Every time I walk in there, it's a resolution.' " The Kid

The external Chris Dodd is perpetually cheerful, an affable joke-teller and story-spinner. His father used to spend Friday nights with constituents in the bars of Connecticut's mill towns, a drinking habit that got to be a problem, particularly during the later years. His son sticks mostly to beer and wine, but people in Connecticut say the younger Dodd is even better at working a crowd than his father. "Give me a room with 1,500 people," Dodd says. "I'm terrible with small talk." When one of his brothers once asked why he'd bought a house so close to the street, Dodd replied, only half-jokingly: "If I had my way, I'd live in the window of Woodward & Lothrop."

But the internal Chris Dodd is a fretter--about his political future, his divorce last year and a life that for all its glitter is lonely. He complains that he gets tired of eating out every night. At 39, he has no children, and that bothers him. "I see it as a void," he says.

He has an almost childlike curiosity. During a weekend of speeches in Connecticut, he stops his car at an inn to show a visitor the proprietor's new set of ovens. "They put ducks in there," he says, fascinated. "Cook 'em at 500 degrees." When he has to pick out a formal morning coat for a Saturday historical parade, he spends half an hour trying on costumes, giggling as he puts on a top hat. "He's a kid," says his friend Michael McAdams.

Sometimes it's hard to remember that he's a senator. He looks like one: premature, neatly sprayed gray hair, dark eyes with bags under them, crisp white shirts, dark blue suits, red ties, collar pins. It is the handsome, distinguished look of a United States senator, but he still seems a little like the guy in college who recently cut his hair for the first job interview. Some people have a difficult time taking him seriously. In the Senate dining room, the middle-aged waitress calls him "my nice little baby." He blushes. When a page comes to tell him it's time to vote, he gets confused and asks, "What?" The page looks straight at the United States senator and, with an impressive display of teen-age impertinence, announces: "You look like I feel." Dodd bursts out laughing.

He is infamous in Connecticut for getting into a doughnut fight. Just as the bars were closing at the headquarters hotel for the Democratic midterm convention in 1978 in Memphis, Dodd, Rep. Harold Ford (D-Tenn.), plus two dozen reporters and White House aides, climbed aboard a bus for a quick stop at Graceland, Elvis Presley's mansion. The party moved on to the Dunkin Donuts shop. Dodd and Ford charged in, told the waitress "don't worry," then went behind the counter and began passing out doughnuts. Soon the glazed and jelly-filled were flying. Dodd was the last to reboard the bus, and when he did, he was pelted with more of the same.

Several weekends ago, when he stops in between speeches at his home, a renovated 19th-century white frame schoolhouse in East Haddam, Conn., he takes off his tie, removes his socks, finds a spot of sun, a glass of Dubonnet, a pack of cigarettes, and then, as a button pops mid-chest, climbs into a deck chair. For half an hour, he gossips contentedly about the love affairs of his friends. The Connecticut River flows in front of him, several hundred yards away across a sloping green lawn. Inside, his place has an expensive summer-house feel: gleaming wood floors, bare white walls, Haitian art downstairs, geraniums in big wooden tubs.

He takes a long drag on his cigarette, then mentions Bianca Jagger without being asked. Friends say he was completely taken with her, sometimes to the point of calling them up and saying with wide-eyed excitement, "I've got somebody in my office I want you to meet. You don't know her--but you've heard of her." Others thought that dating a well-known habitue' of Studio 54 was the last thing a serious U.S. senator needed. "I never worried about that," he says, petulantly.

"It went on for two months, and they were teriffic together," says McAdams. "They would talk and laugh and giggle. It was nice for him to call someone, instead of me, and say, 'Here's what I did today.' What can I do for him? I can't put my arm around him. For a while, it overrode his career--and that was good."

For six years he was an undistinguished representative in the House who was telling friends he was thinking of getting out altogether. Then Abraham Ribicoff, Connecticut's Democratic senator, announced his retirement in 1980. Dodd wanted his seat, but so did Toby Moffett. Moffett, the other young, liberal congressman from Connecticut, had been much more prominent than Dodd in the House, emerging as a maverick who shaped the crucial energy issues. Dodd, who was highly popular in Connecticut, was the party pol who went to clambakes back home. They made a deal: Moffett agreed not to challenge Dodd in the 1980 primary, on the condition that Dodd campaign for Moffett in 1982 when a Senate seat was up again. Dodd won. But in 1982, some say Dodd didn't uphold the deal.

"He spent one-half of one day traveling with me--okay?" Moffett says, the loser in a close race to GOP Sen. Lowell Weicker. "I'm not going to draw any conclusions from that. I just don't want to talk about it." Moffett staffers claim Dodd was in fact undercutting them, and even Dodd says Moffett once confronted him and asked why Dodd was telling major contributors that Moffett was a loser--a charge Dodd denies. "Absolutely ridiculous," he says. "There was not a speech I gave where I did not make him the principal focus of it. There was not a meeting of the campaign finance committee where I did not try to get him more money. But could I have done more?" He shrugs, exasperated. "I suppose." The Senator

Dodd is liberal enough to have recently attracted the ire of the conservative press. Human Events, the conservative weekly that is Ronald Reagan's favorite newspaper, calls his career an "odyssey from liberalism to far left," adding that "his current pronouncements would allow a virtual takeover by foreign Communists of a huge chunk of Central America." Dodd has opposed funding for the MX missile, was one of eight senators to vote against Reagan's historic tax cut in 1981 and is in favor of federal funding for abortion--although as aCatholic, "I'm not comfortable with the notion of turning a significant number of women into murderers." He thinks it's a good idea to negotiate with the guerrillas in El Salvador, then admits, "I realize that's riddled with risks."

After he called the administration policy a "formula for failure" in his April 27 rebuttal to Reagan's Central American speech, he got 450 calls, 4,000 pieces of mail, high praise--and attacks. No one was lukewarm.

"Demagogic and irresponsible," said U.N. Ambassador Jeane J. Kirkpatrick. "The most congested stretch of ignorance and sentimentality ever delivered this side of a junior high school forum," wrote conservative columnist William F. Buckley. Sen. Edward Kennedy (D-Mass.) said it was "terrific" and Sen. Lowell Weicker (R-Conn.) called it "right on target," but many in Dodd's own party felt he had gone too far. "Florid rhetoric," assessed House Majority Leader James Wright of Texas, who said the speech should never have been given. In 10 minutes on network television, many thought Dodd had managed to make himself as controversial as Reagan.

His liberalism and knowledge of Latin America comes in part from his two years in the Peace Corps. He speaks fluent Spanish, and as he said in his response to Reagan's speech, "I've lived with the people in this region . . . they can't afford to feed their families when they're hungry." But the liberalism is also from his father. Thomas Dodd, best known as a militant anticommunist, was a progressive on social issues.

In a commencement speech several weeks ago to the Hamden Hall Country Day School near New Haven, he evokes the names of John F. Kennedy, Martin Luther King Jr., Selma, Ala., the Peace Corps. Then he tells the students about Reagan's "brilliantly conceived" question for the 1980 debate: "Are you better off now than you were four years ago?" Dodd, dressed in a bright red graduation gown, standing behind a podium in the gym, begins to get worked up. "Are you better off?" he asks, angrily. "Not me, our families, our communities, our country. Just you. It had taken just 20 short years for John Kennedy's challenge to be turned on its head. The challenge of the 1980s had become: What has your country done for you?" The 18-year-olds listen politely, but it is on the faces of the teachers, many of them the same age as he is, that you can see the memories he evokes.

Later in the day, in a Hartford speech to executives at Heublein, the distilled spirits manufacturer, he tells them he can't promise he won't vote for higher taxes on liquor. When one of the executives gets annoyed, Dodd becomes flushed and angry.

"Too many people in my business go from audience to audience, and they tell them what they want to hear!" he says, pounding his fist on the podium. "If you want me to stand here and say"--he pounds the podium again--" 'I promise I'm never going to raise excise taxes,' I mean, that's the problem! People go around and they've got a promise for everybody!" Afterward, he grumbles that the executives were probably all Republicans.

He has come a long way from his days in the House, when staffers remember how badly he blew a hearing of the Assassinations Committee in September 1978. Former CIA Director Richard Helms ran over him when Dodd questioned him about CIA plots to assassinate Fidel Castro, although Dodd, cocky and underprepared, had joked the night before that he was going to wear a handkerchief in his pocket, just like Helms. But when Dodd blustered the next day with convoluted questions about "his difficulty" understanding the CIA's motives, it was Helms who stayed cool.

"I can understand your difficulty, Mr. Dodd," Helms responded condescendingly, ignoring the question. "I am just sorry. It is an untidy world."

Afterward, Dodd turned toward his staffers, red-faced. "Do you think I did all right?" he asked, looked for reassurance. They said yes, but they weren't telling the truth.

Three years later, things had changed. The new senator from Connecticut was a member of the Foreign Relations Committee, and was grilling Ernest Lefever, the nominee to be assistant secretary of state for human rights, about Lefever's ties to the Nestle Corp.--which would be a conflict of interest. Dodd wanted to know who had recommended that Lefever use a certain public relations firm to help distribute an article favorable to Nestle.

"A friend of ours recommended it," Lefever responded, uneasily.

"Who is the friend?" said Dodd.

"I think that is irrelevant."

"Why don't you let us decide that? Was the friend associated with the Nestle Corporation? Yes or no?

"The friend was interested in the subject."

"Was the friend associated with the Nestle Corporation?"

"The friend had occasionally done consulting work for the Nestle Corporation."

"So he was associated with the Nestle Corporation."

"That's correct."

Minutes later, Lefever asked for a recess for a "medical problem," then rushed from the room. The Foreign Relations Committee eventually rejected his nomination, and Lefever withdrew.

Since then, Dodd has become a respected member of the Foreign Relations Committee. It was Dodd who offered the 1981 amendment mandating that El Salvador meet human rights requirements before receiving U.S. military aid, winning that debate against Jesse Helms (R-N.C.) on the Senate floor. And it was Dodd, a year later, who introduced the amendment cutting back 1983 El Salvador aid by $100 million--the Reagan administration's first major foreign aid defeat. The Fun, the Strains ------

"If anyone said that Chris was going to be a senator like his dad, I would have questioned it," says Bruce Ellis, who went to Georgetown Preparatory School in Rockville with Dodd. "He was just a good old Joe who got real smart in a hurry." While his father was a senator, Dodd lived in Georgetown. He and his friends, "the fun bunch," according to Ellis' identical twin, Jeff, went to the Georgetown bars on weekends, made trips to Ocean City, traded girlfriends and got together at the Roma restaurant on Connecticut Avenue. On Saturday nights they would sometimes sneak into Dumbarton Oaks and go swimming in the pool.

At Providence College, a Catholic school, the fun continued. "I had a wonderful time," says Dodd. "I studied, but I wasn't a bookworm. I mean, I didn't take it seriously." He says he didn't grow up until the Peace Corps. He was a rural community developer, overseeing 20,000 people in 11 villages in the mountains of the Dominican Republic. He came back to the United States in December 1968. In two years, the country had radically changed. "I wasn't politicized," he says. "I had a whole different perspective on the world. I felt very positive about things." He soon married Susan Mooney, who was working in his father's office. They moved to New London, Conn., and Dodd became a country lawyer. His father died in 1971, his mother in 1973. The next year, an old friend of his father's asked him to run for the House. He came in with the Watergate class of 1974. He's sorry neither parent lived to see it.

"Oh, it would have been wonderful," he says. "It would have been impossible and wonderful. My father would have been calling me every hour. We were very close, particularly in the later years. He was not good with children. Even though he had six kids, he wasn't the kind of guy to go fishing, or to whack a baseball. Where my father began to get really wonderful was as you got older. He was well-read, he loved poetry, he loved to debate. It was wonderful getting older."

By January 1982, Dodd and his wife were separated; they divorced 10 months later. He blames politics, in part. "It was so destructive," he says. "She didn't come down to Washington, and maybe she should have. We ended up having--the way she described them-- 5 o'clock conversations. What do you talk about? She didn't want to hear about legislation. There was no common ground. You come home on weekends and you work. It's just not good. And we didn't have kids. It was no one single thing, for God's sake, that does it, that eats away at it. I come from a strong, closely knit family. You didn't get divorced. So it was really hard."

His ex-wife, who writes fiction, lives in Rhode Island and doesn't have a phone. "She's very serious about her work," he says. Later, he adds: "Sure, there's a sense of failure. You certainly don't go into it with a sense of failure. It does bother you." But he refuses to place the entire blame on his political career. "A lot of it was just fate," he says. "There have been only 17 senators from Connecticut in this century. Fifty, I think, in 200 years. I could have lived another 20 years before a Senate seat would have opened up." Looking Up

Chris Dodd went back to the church five years ago when his marriage was in trouble. Now he tries to go every Sunday. He believes in the divinity of Christ and in the Holy Trinity. When he thinks about God, he says, he thinks about "a far more universal concept than I suppose would be traditional. But he thinks about Him.

And does he think that his father knows what became of his fifth son, the junior senator from Connecticut?

"Yeah," says Dodd, somberly. "I think he knows."