Originally Posted by
bostontraveler
well that would make more sense because showing a US drivers license to check in in a foreign country would be a little odd...
I don’t have a US driver’s licence, but most developed countries will accept any photographic formal ID - just not all, as has been suggested here. As often, the truth is somewhere between the two suggested extremes. In the last 3 years I’ve probably been to about 60 countries of which I think 5-10 have insisted on my passport instead of my ID card from an obscure island region of a country.