Obamacare has made great strides toward its signature goal: to reduce the number of Americans without health insurance. Unfortunately, another important goal — ensuring that everyone's insurance policy provides adequate coverage — remains under siege in the courts and Congress.

Before the Affordable Care Act, private health insurers were free to exclude coverage for all sorts of care. In 2011, 62 percent of people who bought their own policies had to pay for maternity care out of pocket; 34 percent had no coverage for substance abuse services; and 18 percent weren't insured for mental health care. One in 10 had no help buying prescription drugs.   

Moreover, if anyone's medical expenses grew too high, insurers could cut them off. In 2009, one-third of family health plans bought on the individual market had lifetime limits on coverage. Even for job-based insurance, which is usually more generous, 12 percent of people with single coverage faced annual limits. A serious or complicated illness or injury could leave people essentially uninsured.