Sen. Joseph I. Lieberman (D-Conn.), who made history in 2000 as the country's first Jewish vice presidential nominee, today declared his candidacy for president in 2004, pledging to "rise above partisan politics" to fight terrorism, fix the economy and bring civility to public life.

Surrounded by friends, family and classmates, Lieberman made his announcement in a small, crowded auditorium at his old high school in this suburb of New York. His day also included a talk with students in a history class, a visit to a local diner and a round of interviews at the home of his mother, Marcia, 88.

"My friends, two years ago we were promised a better America, but that promise has not been kept," Lieberman said. "So today I am ready to put our country first to fight for what's right for the American people. I am ready to protect their security, to revive their economy and to uphold their values."

In the spirit of his pledge to avoid excessive partisanship, Lieberman's statement of candidacy did not mention President Bush by name, a contrast to some of the rhetoric emanating from other Democratic presidential candidates. That did not stop him, however, from launching a series of criticisms at a news conference.

Lieberman said Bush's new economic plan won't provide enough stimulus quickly enough. The administration, he said, has "mishandled" the confrontation with North Korea, turning it from "a major problem into an international crisis." He also asserted that too many of Bush's policies reward "financial contributors or extreme ideologues."

Lieberman, 60, brings a variety of attributes to the race, beginning with the prominence and experience gained from running on a Democratic ticket that won half a million more popular votes than Bush and Vice President Cheney.

A former chairman of the centrist Democratic Leadership Council (DLC), Lieberman said today he intends to show that he is a "different kind of Democrat," one who embraces many of the party's traditional values but who also has an independent streak.

He begins as the race's most conservative Democrat, a candidate who has credibility on national security issues and long has been one of his party's most hawkish voices on confronting Iraqi President Saddam Hussein. He has a reputation for prodding Democrats to speak more directly about issues of faith and morality, and was one of the first Democrats to rebuke President Bill Clinton for his affair with Monica Lewinsky.

In his announcement, Lieberman promised "to talk straight to the American people," an echo from the 2000 presidential campaign of Sen. John McCain (R-Ariz.), and a sign that he plans to bid aggressively for support from many of the independent voters who backed McCain in his bitter nomination battle against Bush.

The senator also said that no matter what happens in the campaign, he will "know who I am and what I stand for." Lieberman said later that was not intended as implicit criticism of his 2000 ticket mate, Al Gore, who was accused by some of trying to reinvent himself through the course of that campaign.

"It was my way of saying I'm going to be myself in this campaign," Lieberman said.

After the last campaign, Lieberman got into a public spat with Gore, saying it was a mistake for the Democrats to campaign on the theme "the people versus the powerful." His announcement today appeared designed in part to show that while he would embrace many of the same positions he and Gore advocated in 2000, he would do it in a different style.

His quarrels with some of his party's liberal constituencies could put him at a disadvantage in the nomination battle. His crusade against media sex and violence aimed at children has put him at odds with Hollywood and the entertainment industry. His generally pro-business economic views and his support for controversial ideas, such as experiments with school vouchers, also may put him at odds with many Democratic primary voters.

Lieberman will face questions about the implications for the country of having its first Jewish president, from how it might affect relations with Israel to whether his observance of the Sabbath would interfere with presidential duties to the question of whether a Lieberman White House would have a Christmas tree.

An orthodox Jew, Lieberman said today he would continue his practice of not campaigning on the Sabbath but would conduct necessary presidential business on the Sabbath. And he said that a Lieberman White House would have a Christmas tree.

"Obviously, I'm running as an American who happens to be Jewish and not the other way around," he said. "This is all about putting our country first."

Four other Democrats have established presidential committees: former Vermont governor Howard Dean, Sen. John F. Kerry (Mass.), Sen. John Edwards (N.C.) and former House Democratic leader Richard A. Gephardt (Mo.).

The absence of a clear frontrunner could entice others to seek the nomination. Al Sharpton of New York has said he plans to form a committee, and Sen. Bob Graham (Fla.) said he is seriously considering running. Sen. Christopher J. Dodd (Conn.) and Sen. Joseph R. Biden (Del.) Jr. have said they are thinking about the race. Former senator Gary Hart (Colo.), who ran for the nomination in 1984 and 1988, plans a series of policy speeches before deciding.

Lieberman had pledged he would not run if Gore did, but nonetheless spent much of the past two years energetically building support for a possible campaign. He said he hopes to have Gore's support.

The son of a liquor store owner, Lieberman grew up in Stamford and graduated from Yale and Yale Law School. After a decade in the Connecticut Senate, he was elected state attorney general in 1982. Six years later, he upset senator Lowell Weicker, a maverick Republican, and came to Washington.

His history-making bid for the vice presidency vaulted him into public consciousness as he traversed the country with his wife, Hadassah, the daughter of Holocaust survivors.

He spent many days campaigning in Florida in 2000, and his appeal helped the Democrats turn that once-Republican state into the campaign's decisive battleground, but one that ultimately cost the Democrats the race. Today, Lieberman said, "I intend to win."

Sen. Joseph I. Lieberman (D-Conn.) announces in Stamford, Conn., he will seek the Democratic presidential nomination. He was the party's vice presidential nominee in 2000.Sen. Joseph I. Lieberman speaks to a class at Stamford High School, where he announced his candidacy.