copyright 2009, The Washington Post WASHINGTON -- While House leaders are moving toward a vote on health-care legislation by the end of the week, enough Democrats are threatening to oppose the measure over the issue of abortion to create a question about its passage. House leaders were still negotiating Monday with the bloc of Democrats concerned about abortion provisions in the legislation, saying that they could lead to public funding of the procedure. After an evening meeting of top House Democrats, Majority Leader Steny Hoyer, Md., said, 'We are making progress,' but added that they had not reached an agreement. The outcome of those talks could be crucial in deciding the fate of the $894 billion health-care bill. Democrats need the vast majority of their caucus to back the bill, since nearly all congressional Republicans have said they will oppose the legislation. 'I will continue whipping my colleagues to oppose bringing the bill to the floor for a vote until a clean vote against public funding for abortion is allowed,' Rep. Bart Stupak, D-Mich., said Monday in a statement. He said last week that 40 Democrats could vote with him to oppose the legislation -- enough to derail the bill. Nancy Keenan, president of NARAL Pro-Choice America, cast Stupak as 'attempting to ban abortion coverage in the private insurance market.' The abortion dispute centers both on federal subsidies that would be provided for people who cannot afford health-care coverage themselves and the much-debated government insurance alternative, which is included in the House version of the bill but is still being debated in the Senate. Under a 1976 law, federal funds are generally barred from being used for abortions, except in cases of rape or incest or to ensure the life of the mother. Democratic leaders early this summer backed a provision that would allow people to use subsidies under the bill to buy insurance plans that cover abortion, but only funds from individual or employer health-care premiums could go toward paying for an abortion. Effectively, insurance companies would be tasked with segregating money from government payments from those coming from private sources, and only the latter could be used for abortion. But Stupak and some Democrats, along with congressional Republicans, have criticized this provision as an accounting distinction. They say the federal subsidies and the private payments are combined for a person to buy a health plan; therefore, federal dollars are helping fund insurance plans that allow abortions. In July, during the debate on the legislation in the House Energy and Commerce Committee, Stupak unsuccessfully tried to insert a provision that would bar any health care plan that covers abortions from being included in the health-care exchanges the law would set up for people to buy insurance. The Senate rejected a similar effort last month in its bill. Conservative groups such as National Right to Life have also blasted allowing the government-insurance option to cover abortions. They say the cost of such abortions would be paid through the government because it would run the plan. In a letter to House Speaker Nancy Pelosi, D-Calif., signed by 183 lawmakers who Stupak helped organize, a group of mainly Republicans wrote: 'The U.S. government should not be in the business of promoting abortion as health care. Real health care is about saving and nurturing life, not about taking life.' Keenan said a provision such as Stupak's would cut abortion coverage from the health plans of women if their employers decided to enroll in the health-care exchange. But after spending many of the past several days on Capitol Hill working on the bill, she said she wasn't sure if it there are enough House votes to pass it with the current abortion language in it. 'It's too close to call,' she said. 