In the 1500's
Hernan Cortez: "I wish to conquer lands in the New world in the name of the Spanish!"
Aide: "Sorry sir, but you cannot."
Hernan Cortez: "What? Why?"
Aide: "Four Reasons: One, you are too far away to interact with the Native Governments."
Cortez: "Well, yes, but I..."
Aide: "Two, you can only conquer de jure lands for vassals, not for lieges. The King and Queen of Spain do not serve you, you serve them."
Cortez: "That may be, but I..."
Aide: "Three, even if you could declare war on the Natives there, since you have no claim on their titles, you could only conquer one duchy at a time."
Cortez: "Those vile heathens do not have duchies!"
Aide: "Well, that's how the world is organized."
Cortez: "And what exactly is the fourth reason, squire?"
Aide: "Since you own no territory yourself, you cannot raise a fleet to go there in the first place!"