WASHINGTON (CBS DC/AP) — Probing whether the White House shares blame for health care website woes, the House’s chief investigator Wednesday plunged into the technical issues behind the dysfunctional rollout of HealthCare.gov.

Rep. Darrell Issa, R-Calif., chairman of the House Oversight and Government Reform Committee, is exploring a long list of issues: insufficient testing, possible security flaws, design shortcomings – even allegations of political meddling.

But as the hearing went on, there didn’t seem to be a “smoking gun” behind the technical failure that has mortified supporters of President Barack Obama’s health care law and cheered its opponents. The technology’s cost to taxpayers: north of $600 million and climbing.

It was the sixth major congressional hearing since computerized insurance markets went live Oct. 1 and millions of consumers encountered frozen screens. The oversight committee was sharply divided along partisan lines.

“Established best practices of our government were not used in this case,” said Issa. As a result, the law’s promise of affordable health insurance “does not exist today in a meaningful way.” Like other Republicans, Issa wants the law repealed, not fixed.

Ranking Democrat Elijah Cummings of Maryland questioned Issa’s fairness.

Addressing Issa directly, Cummings said: “Over the past month, instead of working in a bipartisan manner to improve the website, you’ve politicized this issue by repeatedly making unfounded allegations.”

A key issue for Issa is why the administration required consumers to first create online accounts at HealthCare.gov before they could shop for health plans. That runs counter to the common e-commerce practice of allowing anonymous window-shopping. Outside experts say it increased the workload on a wobbly system.

Issa and other Republicans suspect a political motive; Democrats say the explanation has to do with technical issues. The shopping feature had its own glitches and would have compounded system problems.

The hearing comes during a week in which the administration is expected to release tightly held enrollment numbers for October. They are believed to amount to only a small fraction of the nearly 500,000 initial signups that officials had projected a month before the trouble-plagued website’s launch.

It also featured Henry Chao, a little-known Medicare official, who had presented an overview of the enrollment system back in the spring, and commented, “Let’s just make sure it’s not a third-world experience.”

Chao is deputy chief information officer for the Centers for Medicare and Medicaid Services, which also is leading the implementation of the Affordable Care Act. A career official who earlier helped implement the Medicare prescription drug benefit, he is widely seen as the operational official most knowledgeable about the health care law’s online system.

Chao’s public comment in March at an insurance industry forum was taken as an edgy joke, and he later joined the parade of administration officials who assured lawmakers that everything was on track for a smooth launch, even as nonpartisan experts from the congressional Government Accountability Office warned that could not be taken for granted.

Issa’s investigators previously grilled Chao in a private session that lasted nine hours. Chao’s name appears on a key Sept. 27 document authorizing the launch of the website despite incomplete security testing. But Issa’s staff has released materials indicating that Chao was unaware of a memo earlier that month detailing unresolved security issues.

On Wednesday, Chao testified that he is confident that the system is secure. In fact, he said he had recommended to his sister that she try it.

Chao was also involved in the decision not to allow anonymous window-shopping, which is available on most e-commerce sites, including Medicare.gov.

He testified Wednesday that the shopping feature “miserably” failed testing and would not have been a help to consumers. Chao said that shortly before the launch he directed a contractor to turn off the shopping feature, and instead apply resources to a more critical function.

Chao insisted there was no political pressure to remove the shopping feature.

“I look at the facts of whether a system is going to be ready,” Chao stated. “In this case, it failed so miserably that we could not conscionably let people use it.”

Issa has suggested a political calculation: The administration wanted to avoid consumers experiencing “sticker shock” over premiums, so it first required them to compute tax credits that work like a discount.

The committee also heard from Todd Park, the White House chief technology officer.

He testified that the website is getting better day by day, and week by week. It can now handle about 17,000 account registrations an hour. Page response times are under one second.

But Park balked when Rep. Scott DesJarlais, R-Tenn., asked what letter grade he would give to the website rollout. “Obviously it’s been really, really rocky,” said Park. “It’s what nobody wanted.”

While questioning Park, Rep. Trey Gowdy, R-S.C., said it was unfair to train wrecks calling Obamacare one.

“It’s been called a train wreck, that’s not fair to train wrecks,” Gowdy said.

Issa has launched high-profile investigations of other troubling episodes for the administration, including the 2012 attack in Benghazi, Libya, that killed U.S. Ambassador Chris Stevens and three other Americans; the failure of the Solyndra solar power company that received government loans; and the “Fast and Furious” gun-tracking program on the Mexican border.

Separately, the House Homeland Security Committee also held its own hearing Wednesday.

It gave Republicans a chance to criticize the health care law and the botched online rollout. But it resulted in few answers on the security of the HealthCare.gov website because officials testifying from the Department of Homeland Security said that wasn’t their responsibility.

While DHS helps federal agencies like Health and Human Services comply with federal security standards, the law leaves many of the technical decisions up to the agencies themselves, the officials said.

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