In the end calls were made, but they had no impact in changing the senator's mind. The senator's wife Vicki, as well as Caroline Kennedy, were apparently very influential in convincing Kennedy to make the move at this time.
Some of it centered around Northern Ireland, where Kennedy was the chief persuader in getting Clinton to grant Sinn Fein leader Gerry Adams a visa in early 1994 despite ferocious opposition from the British government.
That decision worked out very well for both men, giving Clinton one of the great gains of his presidency in foreign policy and rehabilitating Kennedy in the eyes of many Irish Americans who felt he had become too tied to the British and Irish government positions on the North.
The Kennedy endorsement of Obama is not entirely surprising, however. Kennedy has always had a leaning towards the younger dynamic candidate rather than the status quo. He was very taken with Senator John Edwards when he first entered the Senate and saw him as a future president.
Edwards, of course, has disappointed with his poor finishes in the primaries so far, but Kennedy probably felt that Obama represented the last throw of the dice for him in terms of the opportunity to influence a presidential race. At 75, the liberal lion knows he will not have many more opportunities to impact a national election.
Bill Clinton was hardly pleased by the endorsement. He told friends that he had given Kennedy pretty much everything he had asked for during his presidency, and there was clearly a sense of betrayal over Kennedy's surprise move.
But politics ain't beanbag, as has been often quoted in this campaign.
Kennedy staffers were quoted in one report as stating that Obama's support for Kennedy's failed immigration bill was also a major factor in his decision to throw his support to him.
Susan Milligan wrote in the Boston Globe, "Kennedy was also impressed by Obama's deep involvement last year in the bipartisan effort to craft legislation on immigration reform, a politically touchy subject the other presidential candidates avoided, the (Kennedy) associate said."
In fairness to Senator Clinton she supported that bill and voted for all of its provisions, but obviously Obama made a far deeper impression on Kennedy with his backing.
The Kennedy support will certainly be important among Hispanics, where Obama has not matched Clinton in the early primaries. In Nevada they were the margin of victory for Clinton, and they will play a very large role in the vital California primary.
Kennedy also provides a link to the old blue collar, labor coalition that Obama has not convinced to support him during this primary campaign.
The question remains, however, if Obama really is the second coming of JFK, as the former president's brother and daughter clearly believe he may be.
The reality is that those are impossible shoes to fill, as much for the legend as for the reality of the JFK legacy. Obama can only continue to put one foot in front of the other and do his best. The Kennedy endorsement is obviously important, but in the end he will have to achieve greatness on his own dime.
It certainly won't hurt, however, to have the Kennedys in his corner, though some Kennedy family members, most notab-ly Kathleen Kennedy Townsend, the former Maryland lieutenant governor, are sticking with Hillary.
It just adds another fascinating component to an endlessly fascinating race for the Democratic nomination.