A Democratic filibuster of John Bolton’s nomination as United Nations ambassador is “unlikely,” Senator Schumer said yesterday.

Mr. Schumer supported an effort last year to block Mr. Bolton’s nomination from gaining a full Senate vote, but he confirmed that he is considering changing his position.

New York’s senior senator said he was weighing Mr. Bolton’s backing of Israel against his unwillingness to work with other countries at the United Nations. “There’s a good part of Bolton. He’s been a staunch and very good defender of Israel,” Mr. Schumer said on CNN’s “Late Edition.” “There’s a bad part of Bolton. He seems to have a ‘go it alone’ attitude at a time when we need the nations of the world on our side. We’ve seen that in Iran and North Korea.”

Mr. Schumer said he had not made a final decision on which way to vote and that a lot of Democrats were also contemplating their position. The Democrats would need the support of 41 of their 45 members in the Senate to block Mr. Bolton’s nomination. Three

Democrats crossed over to oppose a filibuster last year, meaning that a shift of even a few senators would signal Mr. Bolton’s confirmation. “I think that if you count the votes, a filibuster is unlikely,” Mr. Schumer said.

Mr. Bolton has served as the U.N. envoy for nearly a year after President Bush appointed him during a congressional recess last August. Mr. Bush could reappoint Mr. Bolton again at the end of the year, but some have said it is important for the ambassador to have legislative backing, especially with a war in the Middle East.

Two filibusters last year largely came down to a standoff with the White House over lawmakers’ request for classified documents that Mr. Bolton had asked to see when he served in the State Department.

Although Democrats on the Senate Foreign Relations Committee were highly critical of Mr. Bolton at a hearing last week, the minority leader, Senator Reid of Nevada, has not committed to mounting another filibuster attempt.

New York’s other Democratic senator, Hillary Clinton, supported a filibuster of Mr. Bolton last year but has not said which way she will vote this time. A statement from her office yesterday, after a week of silence, indicated that she is leaning against Mr. Bolton over the document issue.”Senator Clinton remains concerned about the administration’s continued refusal to produce documents to the Senate that are critical to conducting a full and proper evaluation of his nomination,” it said.

Mr. Schumer’s comments yesterday serve as an acknowledgement that the war between Israel and Hezbollah may bolster Mr. Bolton’s confirmation. One Republican critic of the ambassador, Senator Voinovich of Ohio, changed his mind earlier this month.

Both Mr. Schumer and Mrs. Clinton have made statements strongly supporting Israel and the Bush administration’s position on the Israel-Hezbollah war, and they have faced increasing pressure from Jewish groups to show their backing by voting to confirm Mr. Bolton. The Senate will have a recess next month, and a vote could take place in September.