Elizabeth B. Moynihan, the widow of Daniel Patrick Moynihan, the New York senator who, from a hayfield on his upstate farm, helped shepherd Hillary Rodham Clinton into his Senate seat, has endorsed Barack Obama for the Democratic presidential nomination.

In an e-mail statement to the Obama campaign, Mrs. Moynihan, an architectural historian who successfully managed three of her husband’s four Senate campaigns, said she had been inspired by an Op-Ed article by Caroline Kennedy, daughter of the slain president, in The New York Times on Sunday. Mrs. Moynihan added that she was also dismayed at Bill and Hillary Clinton’s recent hostility toward Mr. Obama’s candidacy.

She wrote that her husband, who died in 2003, “would have become excited, as I have, to see Barack Obama rekindle hope in our young as he encourages them to participate in the political process, and I know Pat would approve, applaud and encourage me to join Caroline Kennedy in supporting Barack Obama’s candidacy for the Democratic nomination for president.”

“It is a rare gift to be able to inspire people to share a vision that requires commitment and dedication,” she wrote in the e-mail message, to David Axelrod, a senior adviser to Mr. Obama.