I'd say you're quite optimistic in thinking that not little government implies power =/= authority, and quite pessimistic in thinking that little government does not imply a civilized, functioning society.
But even without getting into political debates which could get really nuanced, can't authority mean capability in this context? I'm not a native English speaker so I'm not sure, but I don't find it odd. It is also possible that these two words have different (Anglo-Saxon vs French) origin, as most of the examples listed, and that their original meaning was synonymous (of course, I'm far too lazy and tired to check that now).
Law is old; in Medieval times such redundancy was considered normal - usually triple - and was very common; presumably it was considered a literate flourish, embellishment and arabesque (sorry couldn't resist a go at it myself.)
But even without getting into political debates which could get really nuanced, can't authority mean capability in this context? I'm not a native English speaker so I'm not sure, but I don't find it odd. It is also possible that these two words have different (Anglo-Saxon vs French) origin, as most of the examples listed, and that their original meaning was synonymous (of course, I'm far too lazy and tired to check that now).