In a short well-written piece on the back page of the opinion section of Sunday's New York Times, the only surviving child of President John F. Kennedy, his daughter Caroline, gave to Sen. Barack Obama what is perhaps the best and most important endorsement he will receive.

Caroline Kennedy has stayed almost entirely away from political life -- even from public life -- since her father was assassinated in 1963. If the public has heard of her, it has been as a low-key activist in childhood education matters and as an author of non-political books for children and about America. In that sense her voice has remained pure, and credible.

Ms. Kennedy has not been the spokesperson for the family, which makes her endorsement of Sen. Obama even more important as a personal act. The visible political leader of the Kennedy family is Sen. Ted Kennedy of Massachusetts, who endorsed Sen. Obama yesterday, after Ms. Kennedy's Sunday statement.

What she says rings like a bell. The article is called, "A President Like My Father." What that means is that she sees Mr. Obama as capable of calling forth the same hope for America that her father did in his time. She says poignantly that she has never had a president who inspired her the way people tell her that her father did. "But," she says, "for the first time, I believe I have found the man who could be that president -- not just for me, but for a new generation of Americans."

Ms. Kennedy's endorsement, coming on top of Mr. Obama's emphatic victory in Saturday's South Carolina primary in the face of the hammering that former president Bill Clinton administered to him during pre-election campaigning in that southern state, sends Mr. Obama forward into the Feb. 5th multi-state contests with serious momentum.

Ms. Kennedy doesn't say it, but it is interesting that criticism of her father in the 1960 campaign turned to no small degree on his alleged lack of experience as a 43-year-old senator to prepare him for the presidency. That didn't stop him from winning, or -- as president -- from leading us as a nation toward a bright future.

President Kennedy's few years as president have been the benchmark for hope for Americans ever since. His daughter is saying that Mr. Obama could be that for us now in this time of grave need for brighter prospects.

The primaries are far from over -- and Mr. Obama's candidacy may yet be found wanting. But Ms. Kennedy has explained his appeal better than anyone else.