Oh gosh I never noticed Sardinia being misspelled on the map! Just a proofing error I guess. Lucky that it’s a very unimportant territory for the game.
@Running-Away Per page 22 of the rulebook, units of another power may be transported only if that power is friendly. Per page 12, the US is not considered to be either friend or enemy to any other power while it remains neutral. Therefore, the US cannot transport units belonging to any other power while it is neutral.