President Trump is vowing to return to two of his favorite goals in 2018: a crackdown on immigration and the dissolution of the Affordable Care Act.

When congressional Republicans passed the sweeping tax bill in December, they eliminated the A.C.A.’s health care mandate. But President Trump wants to knock out the entire program.

As I have learned in the past four years, immigration and health care in America have an organic relationship that may escape the president and his supporters if they experience health care only from the outside looking in.

I’ve been an active pilgrim in our medical culture, as a cancer patient, a kidney stone carrier, a victim of a mysterious vertigo condition and the owner of a battered elbow resulting from a hard fall on a New York City street.