WASHINGTON (AP) -- The Senate has defeated a Republican effort to roll back President Barack Obama's policy on contraception insurance coverage.

The measure sponsored by Missouri Sen. Roy Blunt, a Republican, was defeated 51-48. The measure, an amendment to a pending transportation bill, would have allowed employers and insurers to opt out of portions of the president's health care law they found morally objectionable. That would have included the law's requirement that insurers cover the costs of birth control.

Republicans said it was a matter of freedom of religion; Democrats said it was an assault on women's rights and could be used to cancel virtually any part of the law.