The federal health law directs the states to create markets where people can buy coverage with the help of government funds.
"California is a trailblazer in setting up the exchange," says Peter Lee, who directs California's Health Benefit Exchange.
Lee says he thinks the U.S. Supreme Court will uphold the Affordable Care Act. But even with no mandate to buy insurance, the exchange would still vastly expand coverage in the state, he says… minus a few hundred thousand people.
"The reason the exchange is going to have, we project, over two million people in it after a few years, is it's very little to do with the mandate," says Lee. "It has to do with we're a place where people can get subsidies for care, and can make informed choices."
Anthony Wright of Health Access, a health care consumer advocacy coalition, says the success of the exchange will hinge on having as many people participating as possible - and making coverage affordable will be a deciding factor.
"If the exchange ends up with just sick folks and not healthy folks," according to Wright, "that will not give the exchange the best ability to bargain for the best possible price and the best value for the consumers in it."
Lee says the exchange has received over 40 million dollars from the federal government to set up the new health insurance system.