Senator Clinton beat back a strong challenge by Senator Obama today to win her adopted state in one of the most compelling state primaries in years. Senator McCain defeated a former Massachusetts governor, Mitt Romney, to claim all of New York’s Republican delegates.

Although Mrs. Clinton won New York, Mr. Obama seemed poised to get a big chunk of New York’s 232 Democratic delegates. The Associated Press made its call based on surveys of voters as they left the polls.

Mrs. Clinton was tested by Mr. Obama in heavily black neighborhoods in New York City and liberal upstate stretches and on college campuses in his campaign to be the nation’s first black president.

In the Republican primary, Mr. McCain had the backing of Mayor Giuliani in his quest for the state’s 101 winner-takes-all delegates. Mr. Giuliani ended his campaign last week after a poor showing in Florida’s primary, the latest of several defeats after leading the Republican field months ago.

A WNBC/Marist Poll last week found most New Yorkers felt Mrs. Clinton was best able to handle the economy, the Iraq war and health care, but Mr. Obama embodied the best chance for undefined “change.”

At an elementary school today, Mrs. Clinton with her husband and daughter signed autographs on sample ballots for people at the polling place.

“If voters ask themselves who they think would be the best president, and if Democrats ask who they think would be the best candidate to win, I feel really good about the answers to those questions,” she said.

Of New York’s 232 Democratic delegates, 151 will be split based on the vote in each of the state’s 29 congressional districts and the remaining 81 will be divided based on the statewide popular vote. A Democratic candidate must get 15% of the vote in a congressional district to earn delegates.