Senate Finance Chairman Max Baucus (D-Mont.) indicated Thursday that bipartisan negotiators are considering a potentially controversial citizen verification component for their health care reform bill.We spent some time talking about how one proves ones status to be eligible ... to prove that youre a citizen, Baucus said of the bipartisan gang of six negotiations that occurred earlier Thursday. Illegal residents are clearly excluded.Baucus said the group would likely mandate the use of Social Security numbers as a way of verifying citizenship for the purpose of accessing the new programs and benefits under the bill he is crafting. However, he said there would be alternatives to using SSNs, because some citizens do not have such identification numbers.Baucus also hinted that he might not release his bill on Sept. 15 as he said he would earlier this week. Instead, he said it would be released on that date or very close to the 15th.Still, he plans to introduce the bill sometime next week and markup the measure the week of Sept. 21. Baucus said the markup would likely take three or more days to complete.Generally, Finance committee markups are a matter of a day or two, but ... this is very important legislation so I expect to go longer, he said.While Baucus continues to negotiate with the gang of Senators on the Finance panel in the hopes of producing a bipartisan bill, he has vowed to introduce legislation and mark it up with or without Republican support.Besides Baucus, Finance negotiators include ranking member Chuck Grassley (R-Iowa) and Sens. Kent Conrad (D-N.D.), Jeff Bingaman (D-N.M.), Olympia Snowe (R-Maine) and Mike Enzi (R-Wyo.).