St. Thomas on usurpation of temporal power

[Geremia]

Integralism ch. 5, last § ("Usurpation of temporal power"), quotes Super Sent. lib. 2 d. 44 q. 2 a. 2 ("Utrum Christiani teneantur obedire potestatibus saecularibus, et maxime tyrannis") co.:

The one who seizes dominion by violence does not become truly the superior or lord; and therefore where there is the possibility, one can drive off such dominion, unless perhaps afterwards he is made truly lord either through the consent of the subjects or through the authority of a superior.
 
qui enim per violentiam dominium surripit non efficitur vere praelatus vel dominus; et ideo cum facultas adest, potest aliquis tale dominium repellere: nisi forte postmodum dominus verus effectus sit vel per consensum subditorum, vel per auctoritatem superioris

[Kephapaulos]

I need to read that book!

Would that mean the French Third, Fourth, Fifth Republics have been legitimate if they were recognized as such by the Holy See, even though they have usurped the place of the King of France?

[Geremia]

Would that mean the French Third, Fourth, Fifth Republics have been legitimate if they were recognized as such by the Holy See, even though they have usurped the place of the King of France?

Yes, that's approval "through the authority of a superior", the spiritual power.
(The temporal power is subject to and can be judged by the spiritual power; cf. Integralism ch. 5 §"Temporal power is subject to spiritual power".)

[Kephapaulos]

Still, it would be nice if France had its monarchy restored though.

It is a great temptation to usurp in these our times considering how far man has fallen into sin on both the part of the people and rulers.