John Kerry, the defeated Democratic candidate in the 2004 presidential election, has thrown his weight behind Barack Obama, offering his endorsement in the key state of South Carolina which holds its primary in just over a fortnight.
Mr Obama, "can be, will be and should be the next president of the United States" and would lead, "a transformation rather than a transition" in the White House, said Mr Kerry, in a swipe at Hillary Clinton.
"Who better than Barack Obama to turn a new page in American politics?" Mr Kerry asked, dismissing critics who have questioned the one-term senator's experience. "We are electing judgement and character, not years on this earth," he said, adding pointedly that Mr Obama was, "right about the war in Iraq from the beginning".
The South Carolina primary on 26 January has taken on greater significance after the shared spoils of Iowa and New Hampshire, and Mr Kerry could yet prove a key ally in the weeks ahead. He not only won the nomination in 2004, but he is a respected elder statesman among Democrats with a strong reputation on national security issues – often perceived as Mr Obama's weakest area.
Mr Kerry also has access to a fundraising network and one of the most sought-after email lists. That list, along with millions of addresses, has now been put at Mr Obama's disposal and should be invaluable for a campaign across the 22 states that hold primaries on 5 February, billed as "Tsunami Tuesday".
Mr Kerry will also be useful as the Obama campaign pushes back at the sharp media practices the Clinton campaign used to unsettle voters in New Hampshire. The Kerry endorsement may also attract more big name backers from the Democratic establishment.
Mrs Clinton has much of the party rank and file on her side, but many high-profile senators have yet to make a call.
There is no word yet on Al Gore's position, although Bill Clinton's vice-president is thought to be more sympathetic to Obama. Another Democratic candidate, Governor Bill Richardson of New Mexico, was due to announce he was dropping out of the race for the White House yesterday after making a poor showing in the two first contests. Both he and Senator Joe Biden, who has also dropped out, will be on the lookout for big jobs in a future Democratic administration.
Mr Richardson can be expected to back Mr Obama, after telling supporters to give him their second preference votes in Iowa. Mr Kerry's endorsement of Mr Obama comes as a slap to John Edwards, who was his running mate in the 2004 election. The two politicians co-operated poorly in the campaign trail and have been estranged ever since.
It was Mr Kerry who first spotted the talent of his fellow Illinois senator. He selected Mr Obama to make the keynote speech at the 2004 Democratic convention, which catapulted the local politician into national consciousness.
If Mr Kerry now takes to the airwaves and goes on the road campaigning for the Obama side it could help counterbalance the influence of Bill Clinton on undecided Democratic voters.
In New Hampshire, Mr Clinton was wheeled out to make a personalised and angry attack on the "fairytale" story of Mr Obama's candidacy. He queried Mr Obama's long-standing opposition to the war in Iraq. The Clinton camp also questioned the sincerity of his opposition to lobbyists and said that he was inconsistent on health care.
Despite angry demands from Mr Obama that they be retracted, the Clinton campaign continues to push these points on its "facts hub" website. The style of attack echoes the black arts used to becalm Mr Kerry's 2004 campaign, in which an organisation calling itself "Swift Boat Veterans for Truth" called his character into question. They made Mr Kerry's war record the issue, distracting voters from President Bush's dodging of the Vietnam draft.
Yesterday Mr Kerry gave a not-so-subtle hint to the Clinton campaign that such attacks would be countered. Voters, he said, "reject the policy of swiftboating".