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 today as insurance markets open around the country. It won’t, however, 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.

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.

“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.”

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.

In states not expanding Medicaid, millions of uninsured people below the federal poverty level will likely be shut out of coverage. That’s the case in Texas and Florida — both of which have large uninsured populations — and in many, but not all, Republican-led states.

It’s because under the law, people below the poverty line — an individual making $11,490, a family of four $23,550 — can get the new coverage only through expanded Medicaid. And the Supreme Court gave states the right to opt out.