So, the throne of Spain had been signed over, by both of the persons who seemingly had some form of “rightful” claim to it – under Spanish law as it existed at the time. Prior to this occurrence, surely Ferdinand VII, and if not him, Carlos IV, was the head of a legal, legitimate government of Spain. They were recognised as such by Spain itself and all other nations, it would seem, with the exception of France.
So there lay in Napoleon's hands a series of legal instruments which declared the throne/government of Spain unclaimed! Further (based on a guess), there was one which designated him as the executor to declare the new monarch - absent a qualifed heir pounding on the door. Carlos and Ferdinand were the petering-out end of a sickly line, eh?
Napoleon was not the first nor the last to dot "i's" and cross "t's" on juridical documents written and approved by those learned in the law in a hollow attempt to justify strange and stupid grand governmental things. If it works, you are a great statesman; if it fails, you are called other things. I must say that in this case, he really screwed-up. The juridical paper-work might have worked if he had used anyone but a family member to plop in the throne. He could have used one of his intelligent Marshals as Regent.
All such speculation aside, the point I am trying to raise is the juridical attitude of Napoleon and his subordinates about the dejure government of Spain.
Naturally they expect that almost all the rest of the world will not recognize the new "king of Spain" because they recognize Napoleon only when he kicks their butt. None-the-less, juridically the king is king.
In the period, there were no niceties about "occuping" powers, etc. in the Law of Nations. In point of fact, the French were not conquering the place; they were there to aid the legitimate monarch in governing his domain.
I clearly understand that view is not the popularly accepted position. However, it is not possible to study history if one insists on not accepting the mental or legal positions taken by historical figures because they are repugnant to one's own beliefs.
Therefore, I opine that the activities of the French military in Spain have to be considered as those taken against a hostile domestic population as directed by the duely constituted government.
Again, I appreciate the sketch. I might quibble with a few points in the defacto part. Overall, it really does help me (at least).