In a coup for House Democrats, AARP will endorse sweeping health care overhaul legislation headed for a history-making floor vote, officials told The Associated Press on Wednesday.

An endorsement from the seniors' lobby was critical when then-President George W. Bush pushed the Medicare prescription drug benefit through a closely divided Congress in 2003. House Democratic leaders are hoping it will work the same political magic for them as they strive to deliver on President Barack Obama's signature issue.

An announcement from the 40-million member group is expected Thursday, said officials with knowledge of the group's decision. They spoke on condition of anonymity because the endorsement is not official yet.

Backing the 10-year, $1.2 trillion House bill is a tricky move for AARP. Many retirees are concerned about cuts in Medicare payments to medical providers, which will be used to finance an expansion of health insurance coverage to millions of working families who now lack it.

Counting votes
Floor votes on the House bill could come as early as this weekend. Asked Wednesday if Democratic leaders had the 218 needed for passage, House Majority Leader Steny Hoyer, D-Md., responded: "We're counting. We're counting."

House leaders moved on Wednesday to shore up support for the measure among the Democratic rank-and-file, even as they sharpened their fight with the health insurance industry.

Last minute changes to the legislation, released late Tuesday night, started a 72-hour legislative clock and cleared the way for votes as early as Saturday.