FALLS CHURCH, Va. (Reuters) - U.S. President Barack Obama launched a new attempt to convince Americans of the advantages of his healthcare overhaul on Wednesday, just six weeks before an election in which the plan has proved more of a liability than a benefit for his fellow Democrats.

Obama traveled to the suburban backyard of a family home in Falls Church, Virginia, to talk about provisions of the new law that will take effect on Thursday, six months after it became law, and highlight his argument that healthcare reform will help control the U.S. budget deficit.

"Sometimes I fault myself for not being able to make the case more clearly to the country," Obama told the audience of about 30 people. He described how Americans paying for health insurance are forced to subsidize those who do not have it, with hospitals passing on the expense of treating the uninsured to insurance companies, which in turn pass it on to clients.

"What they do is, they essentially pass on those costs in the form of higher premiums to the people who do have health insurance," he said.

The event included Americans from across the country who are already benefiting from healthcare reform, the White House said, seeking to put a human face on a law that has seemed to many voters to be mostly a confusing array of new regulations.

Attendees described their personal stories of health crises and benefiting from the law.

Republican critics have railed against those regulations as an expensive and unwarranted intrusion into private business, at a time when the country is grappling with high unemployment and record deficits.

Obama underscored what he sees as the tie between the healthcare act and his plans to cut budget deficit, after criticism that his focus on getting healthcare passed in March distracted from efforts to strengthen the stumbling economy.

"Anybody who's out there who's concerned about the deficit, the single biggest driver of our deficit is the ever-escalating cost of healthcare," Obama said. "So it was

bankrupting families, companies and our government. So we said we had to take this on."

NEW PROVISIONS

One provision that takes effect on Sept. 23 lets parents keep their children on their health plans until their 26th birthday. The White House said up to 2.4 million young adults could gain coverage through their parents.

Another is a measure barring insurance companies from denying coverage to children with pre-existing conditions.

Polls show support waning for the healthcare law, which was passed over opposition from health insurers and intense objections of Republicans, many of whom have vowed to repeal it.

Many Republicans and even some Democratic candidates are running against the healthcare overhaul as they campaign for the mid-term election on Nov. 2, in which Republicans are expected to cut into the Democrats' majorities in the U.S. House of Representatives and Senate.

Republican Senator Lamar Alexander, speaking at the Reuters Washington Summit, said Republicans will lack a needed veto-proof Senate to repeal Obama's healthcare program so will instead move to make "step by step" changes.

He said insurance companies should be allowed to sell policies across state lines, for example, which he said would boost competition and reduce prices.

Administration officials insist that voters will come to love Obama's plan once they realize its benefits, just as the government-run Medicare health insurance program for the elderly has become hugely popular even though it was also passed despite fierce resistance from Republicans.

"Poll after poll after poll shows that no, people don't want to do away with it. They want to give it a chance to get implemented," an administration official said, speaking on condition of anonymity in advance of Obama's event.

"There were people who opposed reform six months ago. Those people still oppose reform and are using scare tactics to scare people about the new law," the official said.

(Additional reporting by Thomas Ferrarro; Editing by Eric Walsh and Doina Chaicu)