UNITED STATES - New Year's Day will bring a fresh test for President Barack Obama's healthcare overhaul, as hundreds of thousands of Americans will begin to use the program's new medical coverage for the first time.
For the nation's healthcare system as well as its politics, the stakes are huge in Wednesday's launch of the program known as Obamacare.
For anxious Democrats with an eye on the 2014 congressional elections, it is a chance for the Obama administration to rebound from the disastrous rollout of the website that enrolls people in private coverage through the program - and show that the White House's effort to help millions of uninsured and under-insured Americans is finally gaining its footing.
Or, as Republican Congressman Fred Upton and other critics of Obamacare warned in recent days, Wednesday could represent the beginning of another debacle that fuels Republicans' push to make dissatisfaction with Obamacare the chief issue in the November elections.
More immediately, the question is whether the program will work as advertised on Jan. 1, after a chaotic enrollment period in which problems with the HealthCare.gov website led to a series of deadline extensions and undermined public support for Obamacare and the president.
Many of the newly insured under the Patient Protection and Affordable Care Act signed up just ahead of a deadline on Dec. 24 to receive benefits on Jan. 1, giving health insurers a tight framework to create accounts that can be accessed by doctors.
One fear, as expressed by administration officials and insurance industry executives, is that some people who need medical care during the first days of 2014 will head to the doctor, only to find there is no record of their new insurance.
That could mean patients would have to pay upfront and submit a bill to their insurance carriers later.