Despite strong support from disability advocacy groups, Republican opposition led the U.S. Senate to reject an international disability rights treaty on Tuesday.

In a vote that fell almost entirely along party lines, supporters were unable to secure the two-thirds majority of senators needed to ratify the United Nations Convention on the Rights of Persons with Disabilities.

The treaty calls for greater community access and a better standard of living for people with disabilities worldwide. The measure’s chief supporter, Sen. John Kerry, D-Mass., said that ratifying the treaty would not require any change to U.S. law, but would afford the nation a leadership role in the international community on disability rights issues. What’s more, Kerry said participation would help ensure that Americans with disabilities would have the same protections abroad as they do domestically.

“This treaty is not about changing America, but about America changing the world,” Kerry said just before the vote, adding that the issue had become unnecessarily controversial in the deeply-partisan body. “This treaty is a test of the Senate. It’s a test of whether this body is still capable of voting for change.”

Eight Republicans joined all Senate Democrats in voting for ratification in the 61 to 38 vote. Former Republican Sen. Bob Dole, who was injured in World War II, also came to the Senate floor to support the treaty.

However, a majority of Republicans, led by Sen. Mike Lee, R-Utah, fought hard against ratification arguing that the treaty would compromise U.S. sovereignty and threaten the ability of parents to determine what’s best for their kids, statements that supporters insisted were not based in fact.

Former presidential candidate Rick Santorum, the Heritage Foundation and the Home School Legal Defense Association rallied their supporters from across the nation to lobby against the treaty. Ultimately, their efforts bested those of more than 300 disability organizations which had united to support ratification.

Senate Majority Leader Harry Reid, D-Nev., called it a “sad day” and said he plans to bring the treaty up for a vote again in the next Congress.

The U.S. signed the disability rights convention in 2009, but Senate approval is needed in order to make participation official. The Obama administration sent the treaty to the Senate earlier this year asking that it be ratified.

Currently, 126 countries around the word have ratified the disability treaty, according to the U.N.