The new Republican leadership in the US Senate, is hoping to ban a rare form of late-term abortion
The proposed legislation, being backed by many on the "Religious Right", now looks likely to gain enough support to make it into law following November's Republican election victory.
The victory would be seen as extremely significant for the pro-life lobby after years of argument, legislative wrangling and legal battles.
"This is the beginning of the end, hopefully, of a very long journey for a piece of legislation we've been debating for more than seven years," the Republican Senator Rick Santorum of Pennsylvania, the chief sponsor of the bill, said as a final debate in the chamber began.
The campaign against partial-birth abortions has been high on the political agenda since a new generation of religiously inspired Republicans swept into Congress in the 1994 mid-term elections.
The ban was approved twice in the 1990s but vetoed by President Bill Clinton. It surfaced again last year, but failed to make it past the Democratic leadership.
According to medical experts, including the American College of Gynaecologists and Obstetricians (ACGO), the procedure in the third trimester is rare. But about 30 states, have attempted to ban it, only to be told by the Supreme Court that their legislation is unconstitutional.
Congressional leaders say the law they are now contemplating has been rewritten to take account of the Supreme Court's objections, something pro-abortion advocates contest.
Any new law is likely to be subject to fresh legal challenges.