If a person chooses not to buy health insurance and then needs care, who should pay?

This week at a Republican presidential debate, moderator Wolf Blitzer offered this hypothetical:

“A healthy 30-year-old young man has a good job, makes a good living, but decides, you know what? I’m not going to spend $200 or $300 a month for health insurance because I’m healthy, I don’t need it. But something terrible happens. All of a sudden he needs it.”

Today’s Question: Who should pay for his health care?