Sen. Charles Schumer (N.Y.), a key member of the Democratic leadership team, reaffirmed his support for the public insurance option Tuesday during his opening statement before a Finance Committee session to mark up the panel’s $856 billion health care reform package.Schumer’s statement — delivered as he lauded Finance Chairman Max Baucus’ (D-Mont.) effort to get a health care reform bill to this crucial stage — signaled that key disagreements among Democrats remain. The Finance bill in its current form includes a nonprofit medical cooperative, rather than a public option, in a bid to earn the support of Republicans and moderate Democrats.“This bill takes a giant step forward,— Schumer said. “But I believe there are things we must do to make it better. I’m a firm believer in a public option. … We also have to deal with affordability.—Schumer said he looks forward to improving the Finance bill in the markup process, the forthcoming merger with health care reform legislation previously passed along party lines in the Health, Education, Labor and Pensions Committee, and in conference with the House.Republicans have cited concerns about how the Finance bill might be changed in the merger and conference committee as a significant reason for their decision not to back Baucus’ proposal.