Health insurance costs could increase for people with pre-existing medical conditions, if a lawsuit filed in February in a Texas federal court has its way. It could also limit their options to secure health insurance if the court verdict takes away existing protections of “guaranteed coverage” and “community ratings” that offer uniform premiums.

The case is now in the spotlight because the Justice Department earlier this month said it would not defend the ACA in the lawsuit, in a rare departure from established practice of the government protecting existing statutes. Essentially, that action by the Trump administration would leave those affected to fend for themselves.…