The United Nations estimates that 650 million people around the world are disabled, about 10 percent of the world's population.
Kerry and other backers stressed that the treaty requires no changes in U.S. law, that a committee created by the treaty to make recommendations has no power to change laws and that the treaty cannot serve as a basis for a lawsuit in U.S. courts.
They said the treaty, by encouraging other countries to emulate the rights and facilities for the disabled already existing in the United States, would be of benefit for disabled Americans, particularly veterans, who want to work, travel or study abroad.
Supporters also rejected the argument that it was inappropriate to consider an international treaty in a post-election lame-duck session. They said that since the 1970s the Senate had voted to approve treaties 19 times during lame-duck sessions.
But in September, 36 Republican senators signed a letter saying they would not vote for any treaty during the lame duck,
The opposition was led by tea party favorite Sen. Mike Lee, R-Utah, who argued that the treaty by its very nature threatened U.S. sovereignty. Specifically he expressed concerns that the treaty could lead to the state, rather than parents, determining what was in the best interest of disabled children in such areas as home schooling, and that language in the treaty guaranteeing the disabled equal rights to reproductive health care could lead to abortions. Parents, Lee said, will "raise their children with the constant looming threat of state interference."
Supporters said such concerns were unfounded.
"I am frankly upset," said Sen. Chris Coons, D-Del., "that they have succeeded in scaring the parents who home-school their children all over this country." He said he said his office had received dozens of calls from home-schooling parents urging him to vote against the convention.
The conservative Heritage Action for America urged senators to vote no against the treaty, saying it would be recorded as a key vote on their scorecard. It repeated the argument that the treaty "would erode the principles of American sovereignty and federalism."