The endorsement of a candidate in the Republican presidential primaries by a former Democratic candidate for vice president is a political event with little, if any, historical precedent in the United States.

Senator Joseph Lieberman of Connecticut, who identifies himself as an “Independent Democrat,” made this dubious piece of political history Monday with a speech in New Hampshire endorsing Republican John McCain for president.

The closest parallel in living memory—the endorsement given by Eugene McCarthy, an unsuccessful candidate in the Democratic presidential primaries, to Republican Ronald Reagan in the 1980 general elections—had far less political significance.

“I know that it is unusual for someone who is not a Republican to endorse a Republican candidate for president,” Lieberman declared, standing by McCain at an American Legion hall in Hillsborough, New Hampshire. “And if this were an ordinary time and an ordinary election, I probably would not be here today,” he continued. “But this is no ordinary time—and this is no ordinary election—and John McCain is no ordinary candidate.”

Lieberman spelled out what he meant by declaring, “When it comes to keeping America safe in this time of war, John has proven that he has the experience, the strength, and the character to be our commander-in-chief from day one.” He added that “when others wavered, when others wanted to retreat from the field of battle, John had the courage and the common sense to stand against the tide of public opinion and support the surge in Iraq, where we are at last winning.”

This is the heart of the matter. Lieberman has thrown his backing to McCain, a Republican senator from Arizona, as the candidate who has most identified himself with the Bush administration’s war policy in Iraq.

Political pundits saw the Lieberman endorsement as a bid to boost McCain’s standing among independents, who are allowed to vote in the New Hampshire primaries. Some suggested that the endorsement could be doing double duty, serving to attract independents who might otherwise vote for Democrat Barack Obama, and thereby assisting his principal opponent, Hillary Clinton.

Others have even speculated about a possible McCain-Lieberman “fusion” ticket in 2008.

Whatever the immediate electoral calculations of Lieberman and McCain, the endorsement says a great deal about the state of the Democratic Party and the entire political setup in America.

Lieberman, it should be recalled, ran on the ticket with Al Gore as the Democratic Party’s vice presidential candidate just seven years ago. He was chosen as Gore’s running mate in a blatant concession to the right wing and its rabid attacks on the Clinton administration. Lieberman had gained national recognition by becoming the first leading Democrat to publicly condemn Bill Clinton over the Monica Lewinsky sex scandal, delivering a sanctimonious speech from the Senate floor that served to legitimize the attempt by the Republican right to oust the incumbent president.

Under the Bush administration, Lieberman emerged as the leading Democratic proponent of US militarism in general and the war on Iraq in particular. In 2002, he and McCain co-sponsored the legislation that authorized the Bush administration to carry out the unprovoked invasion of Iraq in March of the following year.

When he ran as a presidential candidate in the Democratic primaries of 2004, he managed to garner no more than five percent of the vote in all but five of the 24 state primaries in which he participated. This overwhelming popular rejection was the starkest measure of the powerful antiwar sentiments that motivated Democratic voters in that election year.

Yet, when the nominating process was completed and Senator John Kerry chosen as the party’s presidential candidate, it was fundamentally on Lieberman’s platform that Kerry ran, insisting that he was not proposing to end the US occupation of Iraq and vowing that, whatever tactical differences there were with Bush, the US militarist venture must “succeed.”

Democratic voters in Lieberman’s home state of Connecticut delivered their own verdict on their incumbent senator as he sought a fourth term in office in 2006. He was defeated in the primary election by challenger Ned Lamont, a cable TV executive who condemned Lieberman for his slavish support for the Bush administration’s war policy. Most of the leading Democrats running in the current presidential primaries—Hillary Clinton, Barack Obama, Joe Biden—backed Lieberman against Lamont in the Connecticut primary, while John Edwards remained neutral.

Lieberman managed to hold onto his seat, defying the primary election verdict of Connecticut Democrats, running as an independent and defeating Lamont in the general election, thanks principally to the support of the state’s Republicans. His designation as an “independent Democrat” reflects this contested path to reelection, as well as his admission into the Democratic caucus in the US Senate. He has been allowed to keep his seniority and to chair the Senate Committee on Homeland Security.

Having paid no price for his marching in lockstep with the Bush White House on the Iraq war—and condemning fellow Democratic caucus members—Lieberman has now thrown his support to a Republican before the primaries have even begun. The tepid response of the Democratic leadership indicated that he will continue to enjoy political impunity.

“I have the greatest respect for Joe,” declared Senate Majority Leader Harry Reid (Democrat, Nevada), “but I simply have to disagree with his decision to endorse Senator McCain.”

Lieberman and McCain have continued to collaborate closely in the Senate. Last Thanksgiving, the two traveled together to Iraq and returned to proclaim that US occupation forces are “winning” the war against the Iraqi resistance. The two issued a joint statement denouncing the failure of the Democratic-led Congress to pass a new war-funding measure without any conditions, as demanded by the Bush administration, calling it “inexcusable” and “profoundly reckless.” They accused the Democrats of “abandoning [Iraq] to the al-Qaeda fanatics and Iranian-backed terrorists.”

He and McCain jointly sponsored an amendment to the military appropriations bill accusing Iran of “murdering” American occupation troops in Iraq. Lieberman called for the preparation of “aggressive military action against the Iranians to stop them from killing Americans in Iraq.”

For his part, McCain made a joke of his support for military action against Iran, singing “Bomb, bomb, bomb, bomb, bomb Iran” to the tune of the Beach Boys’ song “Barbara Ann” during a campaign appearance in South Carolina earlier this year.

Lieberman is by no means an accidental figure in the Democratic Party. He was the chairman of the Democratic Leadership Council from 1995 until his run for vice president in 2000. This influential outfit, which has steadily pushed the Democratic Party to the right based on a repudiation of social reformism and an embrace of militarism, has included among its leading members both Clintons (Hillary currently chairs the DLC’s “American Dream Initiative”), Al Gore, John Edwards and others prominent in the 2008 campaign.

The decision by Lieberman to endorse McCain is one more indication that, whatever mealy-mouthed antiwar rhetoric is heard on the primary campaign trail, the Democratic Party will in the end support the continued occupation of Iraq as well as the buildup for new and even bloodier wars of aggression, including a potential attack on Iran.