UPDATE 1-Obama readies "new phase" in healthcare debate

* Obama may make major health speech next week

* Official says healthcare debate now in "new phase"

* Poll: Americans say Obama hasn't made plans clear

WASHINGTON, Sept 2 - Faced with falling poll numbers and rising opposition to his reform plans, President Barack Obama is completing a new strategy to strike a deal on his proposals to overhaul U.S. healthcare.

Senior administration officials said on Wednesday Obama, who has staked significant political capital on his goal to revamp the health insurance system, was considering laying out a new approach to the topic in a major speech as early as next week.

The timing comes as Democratic and Republican lawmakers return next week from a monthlong recess punctuated by widely publicized town hall meetings that saw bitter shouting matches over healthcare in front of lawmakers visiting their home districts.

Obama has broad goals of reducing healthcare costs and bringing medical insurance to the some 46 million Americans who do not have it. But opposition has focused on the "public option" -- a proposed government-run health insurance plan that Obama supports as an alternative to private insurers.

The White House, stung by coordinated resistance by Republicans and tepid support from some Democrats, signaled a a sharper tone as a push toward passage of a bill intensifies.

"We are entering a new phase in the debate," said Dan Pfeiffer, White House deputy communications director.

"Congress is coming back from recess and over the last few days key Republicans have made it abundantly clear that they are not seriously interested in a bipartisan solution," he said.

Another senior Obama administration official, speaking on condition of anonymity, said the "new phase" was driven in part by negative comments from two Republican senators, Charles Grassley and Mike Enzi, who have been part of a bipartisan Senate "Gang of Six" group seeking a compromise.

The official said Obama considers now the time to pull together various strands from four bills that have been debated on Capitol Hill as well as other proposals.

"Basically all the cards are on the table," the official said. "The president is considering all of his options on how to advance the debate and get reform passed. This includes possibly laying out a more specific vision. No decisions have been made, though."

Senate Finance Committee Chairman Max Baucus has set a Sept. 15 deadline for his Gang of Six to come up with a bipartisan plan, saying that otherwise he is ready to push a bill through the committee with only Democratic support.

LOSING GROUND, REGAINING CONTROL

In the past month, Americans surveyed in polls have shown increasing concern about Obama's handling of healthcare and his popularity with voters has declined.

A CBS News poll on Tuesday said most Americans found healthcare proposals discussed in Congress confusing and thought Obama had not clearly explained his plans to overhaul the system, his top legislative priority.

"The Democrats lost control of the debate on healthcare and they need to seize the initiative and show people what they are going to do," said Darrell West, director of governance studies at the Washington-based Brookings Institution.

"They still have to answer the basic question of how we're paying for this because there are many different financing plans floating around."

Obama still wants the "public option" on health insurance, which is favored by his liberal base. But it is strongly opposed by the insurance industry, and many lawmakers doubt such an option could pass in the Senate.

As a result, Obama and his aides have put less emphasis on the public option in recent weeks, stressing instead that he wants to increase choice and competition through the most acceptable means possible.

But growing long-term budget deficit projections have added further fodder to critics who say the nearly $1 trillion price tag on reform is too high.

The White House argues that a public insurance entity will help extend coverage to uninsured Americans while creating competition with private companies, leading to lower costs.