U.S. Rep. Erik Paulsen used a hearing on the rocky rollout of the Affordable Care Act health insurance exchange to call attention to what he considers a flawed law that threatens to leave more Americans without care because of high premiums.

Paulsen and others grilled Marilyn Tavenner, head of the Centers for Medicare & Medicaid Services, about the HealthCare.gov website – and the policy that created it -- during a House Ways and Means Committee hearing on Capitol Hill. Her agency was tasked with building and operating the site.

The website is supposed to allow uninsured people to sign up and register for health insurance under the Affordable Care Act, President Obama's health care reform law, but the site has been plagued by problems that have prevented people from completing applications.

"Many independent analysts … have been predicting the higher premiums, these cancellations would be coming, you weren't going to be able to keep your doctor or your health insurance even though the promise was laid out by the president," Paulsen told Tavenner. "Directly from our constituents, we're hearing about these challenges."

Tavenner apologized to Americans, saying the exchange's flaws are "not acceptable" and vowed the site "can and would" be fixed by the end of November.

"How do you know the schedule is going to be kept?" Paulsen asked. "What happens if you miss November 30?"

In defending the website, Tavenner said the "system is working, it's just not working as smoothly or as consistently as we want."

The flawed debut of the insurance exchange is tarnishing the Affordable Care Act, Obama's domestic policy centerpiece designed to offer medical coverage to most of the nation's uninsured.

Paulsen and other members of the Republican-led House have voted more than 40 times to repeal or defund the 2010 health care law. Now, after three years of trying to dismantle the law generally known as Obamacare, Republican lawmakers are now seizing on the website's troubles.

But their efforts haven't come without criticism.

"It's really rich for Republicans to be shedding crocodile tears over the glitches in the website when they have done nothing for four years but try to impede, repeal and defund the law and root for its failure," said Brad Woodhouse, president of Americans United for Change, a liberal advocacy group.

"Are we really to believe Congressman Paulsen gives a spit that Americans are having trouble enrolling in a health plan? This is a transparent attempt by Republicans to score political points around road bumps in the health law's implementation."

Tavenner also faced questions from committee members about the administration's claims that everything was on track for a successful launch. As recently as September, she predicted a smooth rollout.

U.S. Rep. Michele Bachmann was among the House Republicans who signed a letter to President Obama last week, calling for the resignation of Tavenner's boss -- Secretary of Health and Human Services Kathleen Sebelius's -- because of problems with the website.

Last week, her agency hired contractor Quality Software Services Inc., a subsidiary of Minnetonka-based UnitedHealth Group Inc., to be the general manager for the effort to fix the troubled website.