When would a physician not need a license?

Answer 1

There are a few situations when a doctor does not need a license to practice in a specific state. For example, when they are (1) responding to emergencies, (2) while establishing state residency requirements in order to obtain a license, (3) when they are employed by the U.S. Armed Forces, Veterans Administration, or other federal facilities, and (4) when only engaged in medical research and not treating patients.

Answer 2

Doctors who don't have a licence to practice can write, work for chemical companies, be advisors to politicians and others.