WASHINGTON (AP) -- Hillary Rodham Clinton will concede Tuesday night that Barack Obama has the delegates to secure the Democratic nomination, campaign officials said, effectively ending her bid to be the nation's first female president.

The former first lady was not ready to formally suspend or end her race in a speech Tuesday night in New York City. But if Obama get to the magic number of delegates, 2,118, she was prepared to acknowledge that milestone, according to aides who declined to be identified.

Obama is 37.5 delegates shy of clinching the nomination, but he is widely expected to make up the difference Tuesday with superdelegate support and votes in South Dakota and Montana. His campaign was announcing new superdelegate endorsements throughout the day Tuesday.

On NBC's "Today Show," Clinton campaign chairman Terry McAuliffe said that once Obama gets the majority of convention delegates, "I think Hillary Clinton will congratulate him and call him the nominee."

She will pledge to continue to speak out on issues like health care. But for all intents and purposes, the two senior officials said, the campaign is over.

Most campaign staff will be let go and will be paid through June 15, said the officials who spoke on condition of anonymity because they were not authorized to divulge her plans.

The advisers said Clinton has made a strategic decision to not formally end her campaign, giving her leverage to negotiate with Obama on various matters including a possible vice presidential nomination for her. She also wants to press him on issues he should focus on in the fall, such as health care.

Universal health care, Clinton's signature issue as first lady in the 1990s, was a point of dispute between Obama and the New York senator during their epic nomination fight.

Clinton was at home in Chappaqua, N.Y., with her husband, former President Clinton and daughter Chelsea. She was placing calls to friends and supporters and working on a final draft of her speech. She was also resting her voice, which was nearly shot after days of nonstop campaigning.

In a formal statement, the campaign made clear the limits of how far she would go in Tuesday night's speech. "Senator Clinton will not concede the nomination," the statement said.

Clinton field hands who worked in key battlegrounds said they were told to stand down, without pay, and await instructions. Speaking not for attribution because they didn't want to jeopardize their jobs searches, many said they were peddling resumes, returning to their hometowns or seeking out former employers.

Clinton officials have said they would not contest the seating of Michigan delegates at the convention in Denver this August. The campaign was angry this past weekend when a Democratic National Committee panel awarded Obama delegates it thought Clinton deserved.