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Awais Vaid, a certified counselor, right, helps Mandy Wyatt sign up for the Affordable Care Act at the Champaign Urbana Public Health District in Champaign, Ill., on Tuesday Oct. 1, 2013. Watt and Tosha Lockett, of Champaign, left, were the first two to sign up in Champaign for the state insurance marketplace.

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In this Wednesday, Sept. 25, 2013 photo, Maygan Rollins, 22, a field organizer with Enroll America, holds a clipboard with pamphlets while canvassing at a bus stop in Miami. Enroll America is a private, non-profit organization running a grassroots campaign to encourage people to sign up for health care offered by the Affordable Care Act. In less than a week Florida residents can start enrolling for health coverage under the Affordable Care Act.

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AP Photo/Lynne Sladky

In this Wednesday, Sept. 25, 2013 photo, Maygan Rollins, 22, a field organizer with Enroll America, left, talks with Jerry Correa, 27, about his health care options while canvassing at a bus stop in Miami. Enroll America is a private, non-profit organization running a grassroots campaign to encourage people to sign up for health care offered by the Affordable Care Act. In less than a week Florida residents can start enrolling for health coverage under the Affordable Care Act.

Contentious from its conception, President Barack Obama's health care law has survived the Supreme Court, a battle for the White House and rounds of budget brinkmanship. Now comes the ultimate test: the verdict of the American people.

A government shutdown could dampen the rollout Tuesday as insurance markets open around the country. But it won't stop the main components of "Obamacare" from going live as scheduled, glitches and all. The biggest expansion of society's safety net since Medicare will be in the hands of consumers, and most of their concerns don't revolve around ideology and policy details.

People want to know if they can afford the premiums, if the coverage will be solid, where the bureaucratic pitfalls are and if new federal and state websites will really demystify shopping for health insurance. Full answers may take months.

Expect the rollout to get off to a slow start, with some bumps.

People who don't have access to job-based health insurance can start shopping right away for subsidized private policies. Or they can wait to sign up as late as Dec. 15 and still get coverage by Jan. 1. Many will probably want to see how it goes for the first wave of applicants before they jump in.

Glitches are likely to pop up in the new online insurance markets. Over the weekend, several states were still struggling to get plan information to display accurately on their websites. Earlier, the federal government announced delays for small business and Spanish-language signups. A protracted government shutdown could slow needed technology fixes.

Consumers also could run into problems getting their right subsidy amounts. People with complicated tax returns and extended families living under the same roof could find they need personal assistance to work out the issues. Referrals to state Medicaid programs might go smoothly in some states, not so well in others.

"As this unveils, it is going to be very clear that everything can't be done on a computer," Christine Ferguson, director of Rhode Island's marketplace, said in an interview prior to the launch. "But by Day 60 to 120, and the year after that, it's going to get a lot more user-friendly and effective."

The Kern County Department of Human Services hired 61 people to beef up its call center staff to take calls from Covered California -- the state's health benefits exchange -- and to help manage new Medi-Cal cases.

Starting Tuesday, the call center will begin taking calls transferred to it by Covered California to assist people who might be eligible for expanded Medi-Cal next year. The call center will be open longer hours, until 8 p.m. weekdays and from 8 a.m. to 6 p.m. on Saturdays, to take calls from Covered California during the exchange's open enrollment period, which starts Tuesday and continues through the end of March.

"We're hoping everything is a go tomorrow," said Pam Holiwell, assistant director of the Kern County Department of Human Services, on Monday.

Eventually, at least half the nation's nearly 50 million uninsured people are expected to get coverage through the Affordable Care Act, either through subsidized private plans sold in the new markets or an expanded version of Medicaid in states accepting it for low-income adults. Immigrants in the country illegally will be the largest group remaining uninsured.

People who do have access to employer-based plans will also see changes. Starting Jan. 1, virtually all Americans will have a legal obligation to carry health insurance or face fines. Passing up the company medical plan in exchange for a bigger paycheck may no longer be an option. But employees who lose their jobs, entrepreneurs starting their own businesses and people in between school and work could have an easier time getting coverage.

Also as of Jan. 1, a pre-existing medical condition will no longer be a barrier to getting health insurance.

A partial government shutdown, driven by Republican opponents of increasing the federal role in health care, will not stop what they call "Obamacare." Core provisions and benefits are shielded from annual budget battles. If other government services are shut down, the health care overhaul can largely keep going -- much like Social Security and Medicare.

"Shutdown or no shutdown we're ready to go," Health and Human Services Secretary Kathleen Sebelius said Monday. Federally operated markets in 36 states open at 8 a.m. Eastern time. The remaining states are running their own markets.

Polls show the country remains divided over the law, with opponents outnumbering supporters. Nonetheless, a Kaiser Family Foundation survey released over the weekend found 56 percent of Americans disapprove of cutting off funding to expand coverage for the uninsured, as congressional Republicans are pressing to do.

The poll also found people in a fog about what the law means for them. Nearly three-fourths of the uninsured were unaware of the new insurance markets opening to serve them.

-- Californian staff writer Rachel Cook contributed to this article.