Sweet column: Ted Kennedy endorsement for Obama months in the making.

WASHINGTON — Democratic icon Sen. Ted Kennedy will endorse Sen. Barack Obama (D-Ill.) for president today, passing him a generational torch at a rally here attended by his niece, Caroline Kennedy, and handing a disappointment to Sen. Hillary Rodham Clinton (D-N.Y.).

The endorsement of the Kennedys — Caroline, daughter of President John F. Kennedy, announced her support for Obama in a Sunday New York Times column — comes as the highly aspirational Obama campaign has been drawing parallels with President Kennedy and seeking a claim on his inspirational legacy to the nation.

Negotiations with Sen. Kennedy (D-Mass.), ongoing for months and including a series of conversations between Obama and Kennedy, were concluded last week, before Obama’s resounding Saturday primary win in South Carolina. The endorsement was confirmed by Democratic sources.

“I have had ongoing conversations with Ted since I got into this race,” Obama said to reporters traveling with him Sunday.

Discussing Caroline Kennedy’s backing, Obama said her “support and endorsement is obviously an extraordinary honor. . . . For somebody who I think has been such an important part of our national imagination and generally shies away from involvement in the day-to-day politics to step out like that is something that I am very grateful for.”

Landing Kennedy was a major accomplishment for the Obama campaign and is significant, Sen. Dick Durbin (D-Ill.) said when we talked Sunday, because it “gives more stature to the candidate and to the campaign.”

Durbin, who played a role in the negotiations, said “Ted Kennedy and the Kennedy family have defined Democratic politics in America for generations.”

With the exception of former Vice President Al Gore, who so far has not become engaged in presidential politics, there has been no endorsement more sought after than Sen. Kennedy’s. Durbin, who is working on congressional endorsements for Obama, said winning Kennedy’s support “was one of our highest priorities.”

Last October, Ted Sorenson, a speechwriter for President Kennedy, started campaigning for Obama, invoking the late president’s name and acting as a “voucher” connecting Obama to the hopeful era of Kennedy’s “Camelot.”

Sen. Kennedy’s endorsement arrives as Obama heads into the 22-state Feb. 5 contests. His approval will also make it harder for Clinton to press Obama on his inexperience, one of his major weaknesses, according to almost every poll.

“With the possible exception of Gore, it is the biggest endorsement a Democrat can get,” said Democratic consultant Jim Jordan, who advised Sen. Chris Dodd (D-Conn.) before he dropped his presidential bid.

“It’s in every way possible a big deal. It’s one more sign the Democratic establishment is very serious about Obama,” said Jordan.

The Boston Globe reported that Sen. Kennedy will campaign for Obama in key Feb. 5 states, focusing on Hispanics and labor.

The extended Kennedy family is divided between Clinton and Obama. Former Maryland Lt. Gov. Kathleen Kennedy Townsend is a Clinton supporter, as is her brother Bobby and sister Kerry, the children of Sen. Robert Kennedy.

Townsend said in a statement put out by the Clinton campaign that “I respect Caroline and Teddy’s decision, but I have made a different choice.

“While I admire Senator Obama greatly, I have known Hillary Clinton for over 25 years and have seen firsthand how she gets results. As a woman, leader, and person of deep convictions, I believe Hillary Clinton would make the best possible choice for president. She shares so many of the concerns of my father.”