WASHINGTON — The White House, backing away from President Obama's "it's-all-on-the-table" approach initially advocated, prepared to get more involved in the details of a healthcare overhaul that officials once were content to leave to Congress, administration officials said yesterday.

The White House's attention increases as Congress turns to a priority that officials watched in recent weeks drift off what has otherwise been a precise pathway. Even with an Obama-imposed August deadline, many administration aides weren't sure just how much they would be able to accomplish before Congress left for the summer, and Obama has turned to his grassroots supporters to pressure Congress to find a solution.

Covering 50 million uninsured Americans could cost as much as $1.5 trillion over a decade, but Obama has cited the crippling impact on the economy of soaring healthcare costs and society's long-standing need to resolve the problem. Obama and lawmakers say they want to lower costs, ensure choice and provide coverage to those who are uninsured. Obama and his advisers initially let Congress take the lead, remembering what happened when President Bill Clinton took to Congress a plan deemed too detailed and too prescriptive.

Draft legislation from the Senate Health, Education, Labor and Pensions Committee would require employers to cover their employees or pay a penalty and would guarantee coverage for all.

But Obama supports a new public insurance plan that would give all Americans the opportunity of getting government-sponsored care. Private insurers are adamantly opposed, fearing they'd be driven out of business, as are most Republicans. And Obama's team has grown more willing to take the lead.

"If we do nothing, everyone's healthcare will be put in jeopardy," said the president, in his prerecorded radio and Internet address, aired yesterday while he attended D-Day ceremonies in France. "Fixing what's wrong with our healthcare system is no longer a luxury we hope to achieve — it's a necessity we cannot postpone any longer."

Congress still hasn't figured out how to pay for the healthcare overhaul. Obama has put forward some ideas, including cuts to Medicare and Medicaid. Others he's suggested, including limiting some high-income tax deductions, have already gotten shot down on Capitol Hill.