Michael Tanner of the Cato Institute devotes a National Review Online column to explaining why increased health insurance enrollment will not necessarily translate into increased access to health care.

Obamacare, as its advocates increasingly point out, has succeeded in expanding the number of Americans with insurance. Even though this achievement came at enormous cost, still leaves millions of Americans uninsured, and dumped millions more into Medicaid, this is still one of the few “successes” that the health-care law can claim.

However, health insurance and access to health care are not the same thing. And evidence is growing that Obamacare is likely to make it harder for us to see a doctor or otherwise obtain care.

Of course, we already know that the limited network of physicians available through most Obamacare exchange-based insurance plans is making it more difficult to see the doctor of your choice. Despite efforts by state regulators to mandate that insurers include more doctors and hospitals in their networks, most Obamacare plans, especially the comparatively low-cost bronze and silver plans, continue to have restricted networks. Nationwide, roughly 70 percent of Obamacare plans offer fewer doctors and hospitals than typical pre-Obamacare plans.

But there is an even bigger issue lurking below the surface.

Even without Obamacare, the Association of American Medical Colleges warns us that we face a shortfall of at least 130,000 doctors by 2025. While both enrollment in medical schools and graduation are up slightly, the increase is nowhere near enough to offset expected retirements. Roughly 40 percent of current doctors are age 55 or over. Moreover, the United States already trails many other countries in the number of physicians per capita, at just 2.5 per 1,000 people. This is compared to nearly 4 per 1,000 in Germany and Switzerland.

Medicine is simply no longer the profession that it once was. In 1970, the average income of general practitioners was $185,000 (in 2014 dollars). Today, even though doctors now see nearly twice as many patients as they did back then, average physician income has fallen to just $161,000. At the same time, the average medical-school graduate now begins his career with more than $170,000 in debt.

Obamacare will squeeze physician incomes still further.