WASHINGTON – The Senate on Friday turned back a Republican effort to eliminate a long-term care insurance program to help seniors and the disabled, saving the plan once championed by the late Sen. Edward M. Kennedy in its health overhaul bill.

But the vote exposed the difficulties Democratic leaders face in persuading their moderates to remain united behind legislation they hope to deliver to President Barack Obama. Eleven Democrats voted with Republicans, who warned that the new program would turn into a drain on the budget.

Republicans fell short in a bid to strike the long-term care plan on a 51-47 vote. The 51 yes votes fell short of the 60 votes needed to prevail.

Two leading Democrats who shaped the health care bill, Finance Committee Chairman Max Baucus of Montana and Budget Committee Chairman Kent Conrad of North Dakota, voted with the GOP.

Known as the CLASS Act, short for Community Living Assistance Services and Supports Act, the idea was originally pushed by Kennedy, the Massachusetts liberal who pursued the goal of health care for all through decades in public service until his death from brain cancer in August.

Workers would pay a modest monthly premium during their careers into the voluntary program. If they became disabled, they would get a cash benefit of at least $50 a day. That can help pay for a home care attendant, for supplies and equipment, make home improvements such as new bathroom railings or defray nursing home costs. A version of the plan was passed by the House. The Obama administration supports it.