Tony Gutierrez, Associated Press
In this Oct. 24, 2014 file photo, Senate Majority Whip John Cornyn of Texas speaks in Dallas. Cornyn, the author of a bill to combat human trafficking is proposing a compromise to resolve a partisan dispute over abortion funding that has hung up in legislation.

WASHINGTON — Republicans sought a way out of an abortion dispute that has blocked anti-trafficking legislation, but Democrats immediately rejected their proposal and voted for a third straight day to stop the bill from moving forward.

The developments Thursday deepened a Senate stalemate over the once widely popular bill to help the victims of human trafficking. The impasse has also stalled confirmation of President Barack Obama's attorney general nominee.

The bill's main GOP author, Sen. John Cornyn of Texas, unveiled a proposal on the Senate floor that would change how a proposed victims' fund operates so that a prohibition on spending for abortion doesn't expand current law. Instead, Cornyn said, the victims' fund would be subject to the same abortion restrictions that have been included for decades in Congress' annual spending bills.

"If we can't get to 'yes' on a human trafficking bill, then heaven help us," Cornyn said as he described what he hoped would be a compromise that could win support from Democrats.

Within minutes, Democrats were rejecting his plan. Sen. Dianne Feinstein, D-Calif., said there could be no compromise on the trafficking bill short of entirely removing a provision that prevents spending for abortions in most cases.

"We want that language out," Feinstein told reporters. "There's a compromise possible: Take it out."

Annual abortion restrictions in current law apply to tax dollars, whereas the victims' fund envisioned by the trafficking legislation would be made up of fees paid by criminals. Democrats say applying restrictions on abortion spending to that new pot of money is an expansion they can't accept. Cornyn's proposal would route the fees through Congress' annual spending process, but Democrats dismissed that as trickery that wouldn't solve the problem.

The back-and-forth came as a vote to move the trafficking bill forward failed 56 to 42, short of the 60 votes needed. Similar procedural votes had yielded similar outcomes for two days, with Republicans joined by a bloc of four moderate Democrats — Sens. Heidi Heitkamp of North Dakota, Bob Casey of Pennyslvania, Joe Donnelly of Indiana and Joe Manchin of West Virginia.

The day's events kept the bill in limbo, its fate uncertain.

Not long ago the legislation enjoyed wide bipartisan support, with all sides agreeing that despite gridlock on so many other issues, they could come together to help sex trafficking victims. That rare unity fell apart early last week after Democrats began objecting to the abortion provision in the legislation, which they claimed they hadn't known about even though it had been in the bill for weeks as it passed the Judiciary Committee unanimously. A Democratic senator's office belatedly conceded this week that a staff aide had actually known about the abortion provision, but claimed the senator, Amy Klobuchar of Minnesota, was not informed.

The legislation is designed to help victims of sexual trafficking, establishing a fund to do so that would receive money paid by convicted sexual traffickers as part of their court cases. The measure says none of the money could be used to pay for abortions except in cases of rape, incest or if the life of the woman were in danger. The legislation also aims to give law enforcement officials more tools to pursue people involved in the human trafficking trade.

Complicating the standoff, Republicans have tied the confirmation of Attorney General-designate Loretta Lynch to the bill by saying that no vote would occur on her confirmation until the legislation passes. That means her confirmation may be delayed until April, because the Senate will next week take up the budget and will then go on recess for two weeks. The long delay has prompted its own round of finger-pointing from Democrats, civil rights leaders and women's groups.