Originally Posted by
RexMundi
Per US Customs, it only works coming from Bermuda, Mexico and Canada, NOT Disney, Caribbean, Europe, etc ONLY BORDER COUNTRIES.
Did you read the state.gov page? The CBP (US Customs) website says the same thing.
You can use the passport card to reenter the United States at sea ports of entry from Mexico, Canada, Bermuda, and the Caribbean. However, if you are not able to return on the cruise ship for any reason (e.g., for an emergency evacuation, you will need a passport book to fly back to the United States.
It actually doesn't explicitly say that you cannot use it from Europe, but you need a passport book to get into Europe so it's not enough by itself to travel. No word on Disney either.