Now that the Supreme Court has ruled in favor of President Obama's health-care law, Washington state will begin working to bring many of its 1 million uninsured onto Medicaid or private health insurance.

State lawmakers and health leaders say they’re grateful that Thursday’s U.S. Supreme Court decision upholding the federal health-care law has ended the legal limbo they’ve all been stuck in since last year.

“This whole case has caused chaos,” said Democratic state Sen. Karen Keiser, chair of the state Senate health-care committee. “Over the last six months, we’ve had nothing but chaos and confusion.”

Now the plan is to move quickly to start bringing a good part of the state’s 1 million uninsured onto health insurance, either public — through a major expansion of Medicaid — or private.

The ruling clears the way for the state, beginning in 2014, to add up to a 500,000 uninsured to Medicaid rolls, and to enroll an additional 300,000 people with low-to-moderate incomes in private insurance, with the help of federal subsidies.

But those implementing the law have reasons to worry.

Federal funding, in a time of political uncertainty, never is totally secure, particularly when the law’s opponents in Congress have vowed to try to dismantle it.

And there are questions whether the primary-care system, already overloaded in many areas, can absorb hundreds of thousands more patients. A state survey of primary-care doctors, done late last year, showed that nearly half said they would not take new Medicaid patients.

Medicaid rolls to grow

Under the expanded eligibility, Medicaid will for the first time insure adults without dependent children or severe disabilities, with incomes up to 138 percent of the federal poverty level.

This influx of patients won’t happen all at once, but it will be huge.

Most of the new Medicaid enrollees, who must be U.S. citizens or have resided legally in the country for more than five years, will be newly eligible for the joint federal-state insurance program, which now covers about 1.2 million in the state. The state estimates Medicaid also will enroll as many as 170,000 others, mostly children, who already have been eligible but not signed up.

For those newly eligible for Medicaid, the law calls for the federal government to pay 100 percent of the costs for three years, phasing down to 90 percent by 2020, with the state picking up the remaining 10 percent. For those already eligible and new to sign up, the state immediately will take on a share of the cost.

Nearly 33,000 people are on the state’s Basic Health program, under a federal waiver. They, too, will be folded into the expanded Medicaid program.

In all, state officials expect the Medicaid rolls to grow by up to 42 percent, and they offer no predictions on the extra cost.

Subsidies for others

In addition, moderate- to low-income people who don’t qualify for Medicaid will receive federal subsidies to help them buy private insurance on the soon-to-be-ready state Health Benefit Exchange, envisioned by the federal law as the marketplace where people can compare benefits, something nearly impossible to do now.

Subsidies outlined in the federal law, given as refundable tax credits, are aimed at people with incomes between 139 percent and 400 percent of the federal poverty level. The federal poverty level, which changes each year, is now $23,050 for a family of four, meaning a family earning up to $92,200 would be eligible for a subsidy, though it would be considerably smaller than those given to lower-income families.

The calculation for the subsidy includes caps on the percentage of income people would have to spend on premiums and on out-of-pocket costs.

The state’s Health Benefit Exchange, which has received federal money to get up and running, plans to be open for “shopping” next fall.

Who’ll treat them all?

Then, when all those folks have their insurance cards and are ready to get some health care, will there be somewhere for them to go?

Many private clinics and doctors now limit or don’t take Medicaid patients, saying reimbursement levels are too low. Beginning next year, the federal law boosts Medicaid reimbursements to doctors to somewhat higher Medicare levels for at least two years.

Washington state has 5,971 primary-care doctors active in patient care — which works out to one doctor per 1,143 state residents — and ranks 13th best among states, according to the Association of American Medical Colleges’ 2010 tabulation of the physician workforce.

But a state survey counted only 5,498 primary-care doctors, and found wide geographic differences in access. About 40 percent of the state’s primary-care doctors practiced in King County, and more than half were age 50 or older.

Aaron Katz, a health-services and global health expert at the University of Washington’s School of Public Health, said if coverage provisions envisioned by the ACA stay intact, “A fair number of people will face a struggle getting access to primary care for a few years while the system adjusts to the ‘new normal.’

“There’s widely held concern adding so many people in short order, even if it’s two to three years, will strain the capacity of primary care providers and organizations (like community and migrant health centers) to serve them,” Katz said in an email.

In Massachusetts, visits to emergency rooms and to community health clinics went up after a similar law was enacted statewide, Katz said. ER visits have leveled off, he said, but visits to the community clinics have stayed high.

Community clinics, which provide care regardless of ability to pay, “have a strong track record at providing high-quality, efficient basic health services,” Katz said.

Even so, hiring staff to see potentially hundreds of thousands of new patients “is a serious challenge we face,” said Steven Wish, director of public policy for the Washington Association of Community and Migrant Health Centers, which represents 26 clinic organizations that together run 170 clinics and cared for more than 770,000 patients last year.

Mark Secord, executive director of Neighborcare Health, which runs seven primary-care and five dental clinics in Seattle, as well as school-based clinics, said gearing up won’t happen overnight. “It takes time,” he said. “But we’ve been thinking about it for some time now.”

Carol M. Ostrom: 206-464-2249

or costrom@seattletimes.com

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