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Carolyn Kaster, Associated Press
President Barack Obama speaks at the Catholic Hospital Association Conference about healthcare reform, Tuesday, June 9, 2015, at the Washington Marriott Wardman Park in Washington.

WASHINGTON — Efforts by insurers to boost premiums are the latest evidence that President Barack Obama's health care law "just doesn't work" and must be replaced, the Republican chairman of the House Ways and Means Committee said Wednesday.

Rep. Paul Ryan of Wisconsin launched the GOP's latest attack against the health care overhaul as Health and Human Services Secretary Sylvia Burwell defended it before his committee. Their conflicting views underscored that Obama's 5-year-old law remains a partisan flashpoint, likely to reverberate through next year's presidential and congressional elections.

Burwell's appearance comes with a Supreme Court decision expected this month on whether subsidies millions of Americans receive under the law are legal. It also comes as health insurers in many states have proposed double-digit rate increases for next year — which Republicans cite as evidence of the law's failures, an assertion Democrats reject.

"Whatever the Supreme Court decides this month, I think the lesson is clear. Obamacare is busted. It just doesn't work. And no quick fix can change this fact," Ryan, his party's 2012 vice presidential candidate, said in prepared remarks.

In a ruling expected within weeks, the justices are expected to decide on conservatives' claims that the health overhaul allowed subsidies only for people in states that created their own insurance marketplaces, not those using the federal HealthCare.gov website. Republicans have supported the suit.

More than 30 states use the federal website and millions of their residents could lose subsidies — which they receive as tax credits — and be forced to drop health coverage they'd find too expensive.

According to excerpts of her opening remarks, Burwell lauded the health care law for "our historic progress in reducing the number of uninsured and improving coverage for families who already had insurance."

Rep. Sander Levin of Michigan, top Democrat on the Ways and Means panel, said in prepared remarks that "predictions of doom and gloom from the other side have certainly not come to pass. No rationing, no destroying Medicare, no bankruptcy."

Obama said Tuesday that his law was now embedded in the country's health care system and said the court shouldn't have accepted the case. He also mocked "unending Chicken Little warnings" from opponents who warned that the law would abridge people's freedom.

"There's something, I have to say, just deeply cynical about the ceaseless, endless partisan attempts to roll back progress," Obama said at the Catholic Hospital Association conference.

A court victory by the conservatives could put disproportionate political pressure on Republicans to help those who've lost subsidies. Of the 34 states likeliest to be most affected by such a ruling, 26 have GOP governors. And 22 of the 24 GOP senators up for re-election next year are from those same states.

Obama has said a "one-sentence provision" could repair the problem if the court bars subsidies for states without their own marketplaces, but Republicans have rejected that approach.

Instead, top House and Senate Republicans have been working privately toward legislation restoring aid to those losing it until sometime in 2017. It would also eliminate parts of the health overhaul, such as its requirement that companies insure workers. That would almost certainly draw a veto from Obama.

Republican lawmakers say they will unveil their plan once the justices rule, though there are no indications they have united behind a particular plan. They hope a Republican will inhabit the White House in 2017 so they can repeal the current law and enact one less expansive.

According to the most recent figures from Burwell's agency, 10.2 million people nationally have obtained insurance coverage under the health law from state and federal marketplaces and started paying for it.

Of those, 7.3 million are from the 34 states most likely to lose subsidies if the plaintiffs win at the Supreme Court. About 88 percent of them — 6.4 million — receive federal subsidies averaging $272 monthly.

As insurers begin filing their premium requests for next year with state agencies, some seeking large increases are blaming unexpectedly high costs from covering more patients under the health care law and rising prescription drug prices.

Regulators can block the requested increases in some states while officials can pressure insurers to curb their increases in others.