The Democratic Party is protecting one of its last anti-abortion members in a safe blue district

In 1990, Patti Ernst was 35 years old and 16 weeks pregnant and found herself in a devastating medical situation. Her water had broken five months early, during a prenatal procedure testing for abnormalities that went horribly wrong.

Her doctors, at a Catholic hospital in southwestern Chicago, said there was nothing they could do. Ernst said they essentially told her “the baby is going to be terribly deformed and probably won’t come to term, but you are just going to have to wait and be pregnant and give birth to...