Health insurance and health care access are two separate concepts. This distinction may seem banal, but it’s often obscured in debates over health care policy. Over the next decade, President Obama’s health care law is projected to expand health insurance to 30 million Americans, but what’s less clear is how well that will translate into an ability to obtain timely, quality and convenient health care.

One of the chief ways that Obamacare seeks to expand insurance starting next year is by setting up government-run insurance exchanges in all 50 states on which private insurers will be able to sell government-designed insurance policies to individuals receiving government subsidies. Several weeks ago, there was a raging debate when California announced details on the plans to be offered on its state exchange. Much of the debate focused on whether the cost of the new plans was too high, especially for younger and healthier Californians. But another important element was that, as the Los Angeles Times reported, “one downside for many consumers will be far fewer doctors and hospitals to choose from.” One of the largest insurers in the state, Blue Shield of California, “said its exchange customers will be restricted to 36% of its regular physician network statewide.” In other words, many Californians who obtain insurance through the exchange could end up with a lot of restrictions to accessing health care.

The other major way that Obamacare expands coverage is by making millions more Americans eligible for Medicaid, the joint state/federal health insurance program for those with low incomes. The problem is that Medicaid pays doctors significantly less than private insurance companies, and as things stand, an increasing number of doctors are refusing to see Medicaid patients. According to a 2012 survey by Jackson Healthcare, 58 percent of general physicians, or internists, say they cannot take on new Medicaid patients — and this is before next year’s expansion.

In order to pay for the roughly $1.8 trillion cost of the health care law’s coverage expansion, Democrats raised taxes and sought to extract savings from Medicare by reducing payments to hospitals and other providers of medical care, in hopes that it would prompt them to cut costs. Paul Spitalnic, the acting chief actuary of the Centers for Medicare and Medicaid Services, warned last month that, if fully implemented, the cuts would reduce Medicare payments rates “considerably below” even rock bottom Medicaid compensation levels.  Spitalnic predicted that, “Congress would have to intervene to prevent the withdrawal of providers from the Medicare market and the severe problems with beneficiary access to care that would result.”

Defenders of government health care could argue, in response to this, that even if the worst predictions of Obamacare critics are realized and patient access is less than ideal, it would still be vastly better than a system in which they’re uninsured. However, this is operating under the mistaken assumption that Obamacare would only impact those receiving government assistance. In reality, when 30 million newly-insured Americans seek care in an already strained medical system without a corresponding spike in the number of doctors, even the currently insured may find it a lot more difficult to obtain care in a timely manner than they can currently. The same Jackson survey cited above projected “significant” attrition among American physicians in the coming years, with more than a third of doctors planning to leave medicine within a decade. The United States will not only need to replace these outgoing doctors, but will have to educate enough new doctors quickly enough to meet additional demand.  With the health care law putting downward pressure on expected lifetime physician compensation, it’s unclear whether a critical mass of college graduates will go through the lengthy and costly training process required for them to become practicing physicians.

As Obamacare races toward implementation, access issues will play an increasingly prominent role in the health care debate.