Joe Lieberman ascended to national prominence by building one bridge at a time. Then, having reached the pinnacle by becoming the Democratic nominee for vice president in 2000, he spent 10 years burning bridges.

Ultimately, Lieberman’s most celebrated bridge — between America’s non-Christian, non-establishment minorities and the highest office of the land — will be his legacy, say both friends and critics.

The U.S. senator from Connecticut, perhaps the nation’s best-known independent, announced last week that he would not be running for re-election in 2012.

In an anxious, jokey appearance in Hartford — he started by likening himself to daytime TV talk jockey Regis Philbin, who also had just announced his retirement — Lieberman’s first serious reference was to his role as a history maker.

“I can’t help but also think about my four grandparents and the journey they traveled more than a century ago,” he said. “Even they could not have dreamed that their grandson would end up a United States senator and, incidentally, a barrier-breaking candidate for vice president.”

“First Jewish candidate on a major ticket” would be the Lieberman legacy to outlast all others, said Ira Forman, the former director of the National Jewish Democratic Council.

“It was an electric moment,” Forman recalled of Al Gore’s choice of Lieberman in 2000. “It galvanized the feeling that everything is open to you.”

Lieberman, an Orthodox Jew, had come to that point through a reputation of independence – but also one of reconciling the seemingly irreconcilable.

In 1998, he delivered a floor speech excoriating President Clinton for his affair with an intern, Monica Lewinsky. He called his one-time friend “immoral” and said that Clinton had “weakened” the presidency.

The speech sent out shockwaves — news networks interrupted broadcasts to go to the Senate floor — but it also staved off calls for Clinton’s removal from office. It was credited with salvaging the presidency when the Senate subsequently rejected the U.S. House of Representatives’ impeachment. Through a Democrat’s excoriation of a Democratic president, Lieberman seemed to have punished Clinton enough.

Lieberman’s reputation for outreach to the other side defined his career in the Senate since he arrived in the body in 1989, having been elected after serving as Connecticut’s attorney general. His breaking with Democratic ranks in backing the first Persian Gulf War in 1991 helped him later in the decade, when he rallied Republicans to support Clinton’s military actions in Kosovo.

In 1992, when Clinton’s campaign was cold-shouldering Arab Americans, the community reached out to Lieberman, despite pronounced differences with him over Israeli-Palestinian issues, because of his reputation for fairness.

James Zogby, the president of the Arab American Institute, tells of Lieberman’s outrage, and how after one phone call from the senator, Clinton’s headquarters in Little Rock, Ark., abashedly opened its offices to Arabs.

Yet it was at his very pinnacle — running for vice president — that signs emerged of how the subsequent decade would play out. He delivered an ineffective performance — some said even deferential — in his debate with Dick Cheney, George W. Bush’s running mate. And during the recount, he undercut one of Gore’s best arguments — questionable absentee ballots from the military — when he told NBC’s “Meet the Press” that they should be honored.

The real turning point came after the Sept. 11, 2001 terrorist attacks, when the Bush administration launched a political and diplomatic campaign to make the case for war against Iraq.

Like many other Democrats, Lieberman steadfastly backed war. But while many of his Democratic colleagues came to regret their decision, he stuck by it, and even made it the centerpiece of his 2004 campaign for the presidency. He was bitter when Gore, who opposed the war, endorsed Howard Dean for president that year.

Lieberman’s adamant backing of the war led to an insurgency in Connecticut. Liberal Democrats descended on the state to back his anti-war opponent, Ned Lamont, helping him win the primary. It didn’t help that at this late stage, when the Iraq war’s failure had become conventional wisdom, Lieberman wrote an Op-Ed in The Wall Street Journal backing Bush’s strategies.

Establishment Democrats, including a freshman senator from Illinois named Barack Obama, supported Lieberman in the primary but could not see a way to support him once Lamont prevailed. Lieberman ranas an independent, and with the Republican Party refusing to back its candidate, he won with votes from the GOP and independents.

In that election, Jewish Democrats were torn between their loyalty to the party and to Lieberman. Notably, the National Jewish Democratic Council stayed out of the fight.

That loyalty helped Lieberman capture a fourth term and proved he still had ties to the Democratic Party.

But that bridge burned when he made it clear that he’d back his old friend Sen. John McCain (R-Ariz.), the GOP candidate, in the 2008 election. Lieberman’s announcement led to a tense, whispered conversation with Obama on the Senate floor in which Obama reminded Lieberman of how he had made time to campaign for him against Lamont.

Particularly galling for Democrats was Lieberman’s agreement to endorse McCain on the floor of the Republican National Convention in Minneapolis. McCain even considered Lieberman as a possible running mate.

“He put himself in a position where his longtime supporters, particularly the hard-core Democrats who had supported him over the years, could no longer defend him,” said Marvin Lender, who raised money for Lieberman in 2006. “I say that recognizing he was a very loyal person to his old friend, but he crossed over a line when he did that and disappointed a ton of people.”

After the election, Obama made it clear that he wanted Lieberman to stay on his side. That meant Lieberman maintained his chairmanship of the Homeland Security committee while caucusing with Democrats.

He still had a bridge or two left to burn: On health care reform — a signature issue for Jewish Democrats — Lieberman equivocated until the last minute, ultimately casting his vote in favor.

His relationship with Obama remained cordial but tense. Lieberman took the lead in criticizing Obama’s approach to Israeli-Palestinian peacemaking as overly confrontational when Obama met last May with Jewish lawmakers.

Lieberman maintained his fierce independence until the end. His career cap was a nod to his more liberal sensibilities, when in the final weeks of 2010 he earned kudos from liberals for enabling repeal in the Senate of the “don’t ask, don’t tell” rule that had made it impossible for gays to serve openly in the military. Gay activists did not fail to notice that Lieberman, a Sabbath observer, stuck out the vote, even though it was on Shabbat.

Yet that also was a bridge burner of sorts. When Lieberman a few nights later attended a Republican Jewish Coalition party celebrating the GOP’s win of the U.S. House of Representatives, at least one GOP donor to Lieberman’s 2006 campaign buttonholed him and said he would never again give him money because of his success in leading the “don’t ask” repeal.

Lieberman smiled, said he had to do what he had to do and left the party.

“Senator Lieberman is a true mensch and a great American,” the RJC said in a statement Jan. 19. “He showed that it’s possible to have a successful political career while doing what you feel is right — even when what’s right is not what’s in your political best interests.”

That’s still open to question. After Lieberman’s announcement last week, New York Times columnist Gail Collins denounced him as a narcissist while fellow columnist David Brooks praised him as a man of principle.

For Jewish Democrats, the tendency may be toward the latter position, even if it’s mostly sentimental.

U.S. Rep. Eliot Engel (D-N.Y.), said he would miss Lieberman, despite their differences over issues such as health care.

“Even if I disagree with him,” Engel said, “I known he’s doing it because he feels it is right.”