What is the difference, between how the EAR and ITAR define foreign nationals for access purposes?

The key difference is that ITAR generally requires licensing for each country of citizenship. ITAR takes into account a person’s country of origin in addition to current residency/citizenship in determining citizenship status. For example, a German citizen born in Germany and present at a university conference will be considered German for ITAR purposes; access restrictions will then follow from how ITAR restricts Germany. However, a Canadian Permanent Resident born in France should be considered both Canadian and French for ITAR licensing purposes. In such cases, unless the country of birth is proscribed under 22 CFR 126.11, this does not present a problem.