From the revised Chapter 8:
Target or targets
Some spells, such as dominate realm, have a target or targets. You cast these spells directly on the target. You must be able to see or touch the target, and you must specifically chose that target.
The need to be able to see (or touch) all targets of Realm Spells is quite contrary to the spirit of most spells that have a range of 'Long'. Would it be more reasonable to expand this to 'You must be able to see, touch or know the location of the target,...'? A regent would know the location of a province, hence be able to cast spells with a Long range without seeing the province. Similarly if one know the location of a unit (in a castle or other garrison) one could affect them from afar, but if they were out in the field one would have to locate them (by sight or other means) for the spell to work.