WASHINGTON — Liberal Democrats failed today to inject a government-run insurance option into sweeping health care legislation taking shape in the Senate Finance Committee, despite widespread accusations that private insurers routinely deny coverage in pursuit of higher profits.

The 15-8 rejection marked a victory for Sen. Max Baucus, D-Mont., the committee chairman, who is hoping to push his middle-of-the-road measure through the panel by week's end. It also kept alive the possibility that at least one Republican may yet swing behind the overhaul, a key goal of both Baucus and the White House.

"My job is to put together a bill that gets to 60 votes" in the full Senate, the Montana Democrat said shortly before he joined a majority on the committee in opposing the provision. "No one shows me how to get to 60 votes with a public option," the term used to describe a new government role in health care. It takes 60 votes in the 100-member Senate to overcome delaying actions that Republicans may attempt.