@puravidapto Two last comments as I overlooked your analogies, just to reiterate how complicated international issues could be.

First, your analogy about recognition of foreign marriage is not valid because that recognition is rested in the long-standing position of the IRS, published as a Rev. Rul. and well tested in case law.

Second, foreign degrees are not recognized automatically in all cases - many a time, that depends on treaties and conventions.  Furthermore, accreditation bodies, especially for professional degrees, in different countries often have different standards and requirements.