Michael Cannon explains for Washington Examiner readers why they should dismiss a popular argument involving the Affordable Care Act and pre-existing health conditions.

If Republicans want to have a prayer of competing with Democrats on healthcare, they need to bury the conventional wisdom that Obamacare “banned” (Elizabeth O’Brien, Time), “outlawed” (Sharon Begley, Reuters), and “ended” (House Speaker Nancy Pelosi) discrimination against patients with preexisting conditions.

Obamacare has not eliminated discrimination against patients with preexisting conditions, and not by a long shot. Jeanne Balvin’s experience shows Obamacare perpetuates some forms of discrimination against the sick. Colette Briggs’s experience shows Obamacare has repealed other forms and replaced them with “backdoor discrimination” that is arguably worse.

Colette Briggs, now 7 years old, received a leukemia diagnosis at the age of 2. On the surface, Obamacare would seem to guarantee she will get the treatment she needs. It requires insurers to enroll her family and to charge it a premium no higher than healthier families.

Under the surface, however, those same rules have pushed Obamacare plans to drop coverage for the only local providers who offer the treatment she needs, which they have done repeatedly for five years.

How does a ban on discrimination against the sick instead encourage such discrimination? To illustrate, let’s say the Briggs family costs $100,000 per year to insure. Obamacare requires insurers to charge the family far less — let’s say $20,000.

From an insurance company’s perspective, the Briggs family represents an $80,000 liability. Each year, the Briggs family will reliably choose whichever plan offers the best coverage for Colette’s illness.

The combined effects of these factors are to threaten insurers with an $80,000 loss if they make the mistake of offering the best coverage for Colette and to force insurers who want to stay in business to compete to make their plans worse for expensive patients, in the hope of encouraging those patients to select a different insurer.