ASHINGTON, May 4 � Bush administration officials said today that the vote removing the United States from the United Nations Human Rights Commission raised questions about the group's commitment to human rights. But the officials vowed that the United States would continue lobbying the body from the sidelines as an observer.

"A commission that purports to speak out on behalf of human rights, that now has Sudan and Libya as members and doesn't have the United States as members, I think may not be perceived as the most powerful advocate of human rights in the world," a White House spokesman, Ari Fleischer, said.

Administration officials said they were stunned by the vote on Thursday, especially because the United States delegation to the human rights group had lined up 43 votes of support, more than enough to win a seat on the 53-member commission. In the end, only 29 nations backed the United States.

Secretary of State Colin L. Powell said today that the United States had "43 solid written assurances" going into this week's tally but lost out in the vote-swapping that is a regular part of the United Nations.

Some allies of the United States, Secretary Powell said, had swapped their votes because they thought the United States had its seat locked up. "They're as astonished as we are about what happened," he said.

But administration officials acknowledged that there were also many nations who voted against the United States deliberately, for reasons that include resentment over the American delegation's criticism of countries that violate human rights and anger over the White House's recent decision not to sign the Kyoto treaty on greenhouse gases.

Secretary Powell said he did not intend to quiz the various member countries to determine which ones reneged on their votes and why.

"I suspect there are lots of different reasons," he said. "I'm not going to spend any of my time trying to break into what was essentially a secret vote to try to find out what happened. We're going to continue to pursue human rights. We're going to put out our human rights reports. We're going to call nations to account when they violate basic principles of human rights."

But others were seeking to piece together the motivations of the member countries. The United States has drawn criticism in recent years for building up a large debt to the United Nations, for rejecting a number of treaties and agreements and, more recently, for rejecting the Kyoto treaty and criticizing the 1972 antiballistic missile treaty as it pursues a missile defense shield.

"I think there's an annoyance with the United States on a variety of issues that is not so far below the surface," said Representative Christopher H. Smith, Republican of New Jersey and vice chairman of the House International Relations Committee.

Still, Mr. Smith, who attended the commission's recent meeting in Geneva as part of the Bush administration's delegation, said he did not understand the human rights vote.

"I happen to be in favor of the Kyoto treaty," he said. "But environmental issues and other issues should not be used to punish the United States when it comes to things like torture."

Lawmakers said the human rights vote would only increase the reluctance on Capitol Hill to participate in international agreements, and might reverse the improvement of relations between Congress and the United Nations that resulted in a deal to pay back dues. In recent years, the United States has declined to join a variety of pacts � including a treaty on land mines, the Law of the Sea treaty and the agreement setting up an International Criminal Court � because they contain provisions opposed by Washington.

"If this is the way the international court is going to adjudicate cases, totally on a partisan basis, that will make the court a complete farce, as well," Mr. Smith said.

The human rights commission, which Eleanor Roosevelt helped create in 1947, has long been a polarized group, which is no surprise given the delicate nature of its subject matter. China, Cuba and other countries have grown adept at using procedural rules to outflank the efforts of the United States to use the commission to condemn them.

On Wednesday, as the commission was voting to exclude the United States, the House International Relations Committee was urging the Bush administration to seek the ouster of member countries that do not allow their human rights situation to be scrutinized.

Former Representative Geraldine A. Ferraro, who led the American delegation to the commission from 1993 to 1996, said today that the Bush administration had not done enough to round up support before the vote.

"This should have been anticipated, and this should have been prepared for," Ms. Ferraro said. "We should not have lost the vote. Eleanor Roosevelt is probably turning over in her grave, and if I were dead, I'd be turning over, too."