By a 51-48 vote, the motion by Democrats to table the amendment succeeded, effectively killing it.
The so-called "conscience" amendment, sponsored by Sen. Roy Blunt of Missouri, was the Senate Republicans' response to the simmering controversy over a recent Obama administration decision to mandate the kind of health care coverage provided by religious employers.
"This bill would just simply say that those health care providers don't have to follow that mandate if it violates their faith principles," stated an early February press release from Blunt. "This is about the First Amendment. It's about religious beliefs. It's not about any one issue."
While Blunt's amendment took a broad approach, the main issue involves whether religious employers should have to include coverage for contraception in health plans offered to employees at affiliated institutions, such as hospitals.
Earlier this month, Secretary of Health and Human Services Kathleen Sebelius issued a directive that would have required all employers, including religious organizations, to include such coverage in health insurance offered to their employees. While churches were exempt, the mandate covered religious affiliated institutions.
Representatives from many faiths opposed the decision, calling it a violation of their religious conscience.
In response to the uproar, the White House backed off the directive and instead said that religious employers could opt out of offering coverage for birth control, but insurance companies would have to offer such coverage separately and at no charge.
Some critics say the White House's changed position does not go far enough.
Blunt's amendment stated the president's health care law, the Patient Protection and Affordable Care Act, imposes requirements that infringe on the rights of conscience of insurers and plan sponsors. While the law exempts some religious groups, it does not allow all those with religious or moral objections to decline providing coverage, the amendment says.
Part of the uproar surrounded universities and hospitals affiliated with religions, which were not given the same exemptions as churches and other religious institutions.
The amendment would have established that an entity refusing coverage on religious or moral grounds is not in violation of the law.
The amendment did not mention contraception specifically.
Just what impact the amendment would have had was a matter of debate. On his website, Blunt rejected complaints that it would have allowed anyone to deny coverage of anything for any reason.
The Blunt amendment had been tacked onto a $109 billion transportation bill, raising complaints from Senate Majority Leader Harry Reid, D-Nevada, that the amendment was not germane to the legislation.
Because of the dispute, action stalled on the transportation bill, which is backed by both parties.
Reid said Tuesday that Senate Minority Leader Mitch McConnell, R-Kentucky, insisted on a floor vote on the Blunt amendment "before we can move ahead with this jobs bill."
"Once we have put this extreme and distracting proposal behind us, I hope my Republican colleagues will stop living in the past and join us this year, 2012, and help us create jobs," Reid said.
Blunt welcomed the vote by tweeting, "Glad Sen. Reid is going to allow a vote on my bipartisan admt to protect religious freedom this Thursday. #HHSMandate."
Voting on the amendment forced senators to take a stand on the controversial contraception decision. Though many Republicans have come out in support of the measure, retiring Republican Sen. Olympia Snowe from Maine told MSNBC the amendment is "much broader than I could support."
Not all Democrats were united against the amendment, however. Sen. Joe Manchin, D -West Virginia, issued a statement Wednesday saying he would support it.
"I am voting in favor of this measure to protect the First Amendment to the Constitution of the United States of America," Manchin said in a statement.
A CNN/ORC International poll earlier this month showed a partisan divide on the issue, with 70% of Democrats agreeing with the Obama administration policy while 85% of Republicans opposed it. Independents were statistically split.
Senator Blunt's Statement On Vote To Protect Americans' Religious Freedom:
WASHINGTON D.C. - U.S. Senator Roy Blunt (Mo.) issued the following statement today regarding the Senate vote to table the "Respect for Rights of Conscience Act" and uphold the Obama Administration's violation of the First Amendment rights of all Americans:
"I am truly disappointed by the partisanship that has been injected into this debate on religious freedoms. Instead of working to pass a bipartisan measure that has been part of our law for almost 40 years, this debate has been burdened by outlandish and divisive efforts to misinform and frighten Americans.
"The fact remains that this provision would simply preserve the fundamental religious freedom that we enjoy today. For the first time in our history, the Obama Administration's health care mandate is an egregious violation of our First Amendment rights.
"Unfortunately, this is only a glimpse of what Americans can expect as a result of President Obama's government health care takeover - which is why we need to repeal and replace this bill with common-sense bipartisan solutions.
"This fight is not over. I will continue to work with my colleagues on both sides of the aisle and in both chambers of Congress to protect the rights that make our nation great."