לזכות שיינדי חנה בת מלכה לברכה והצלחה בכל מעשי ידיה!!
Based on the forgoing, it would appear that Yehoshua was only a king like a שופט, for they too were called kings. For this reason there was a law of לא ימרה את פיך to obligate one who defies his word with the death penalty as a מורד במלכות. He also had a דין מלך with respect to asking of the אורים ותומים since he was a ruler. But it seems that he only had a דין מלך when there was no other מלך among the Jewish people but when there was a מלך he was the only king and there was no other and then all the Nasi [who was like a שופט as we saw] has, is the power of the Av Beis Din of the Sanhedrin but it has nothing to do with מלכות.
This idea is explicit in the Maharsha [Sanhedrin 20b], Chasdei Dovid on the Tosefta [פ"ד דסנהדרין] and the basic idea can be found in the Ramban [Bereishis 49/10] that the complaint Hashem had against the Jews for requesting a king [who it is actually a mitzva to appoint] was that they should not have asked through Shmuel who was already a שופט. And the Meiri says that they wrongfully wanted to replace the Navi with a king. The Ramban said that Shmuel was a שופט and נביא and waged wars for them based on the word of Hashem and saved them. The Chasdei Dovid explained more that since by appointing Shaul, Shmuel was "demoted" and we pasken מעלין בקודש ולא מורידין - one must go up in kedusha and not down, it was wrong to ask for a king. But there should be no problem because he could remain the Nasi of the Sanhedrin and a שופט? The answer is that as we said, there can be no מלכות of a Nasi and שופט when there is a bona fide מלך and through the appointment of Shaul, Shmuel's status as a king was nullified. See also Rashi [נצבים כ"ט י"ב] who writes יוצאים מפרנס לפרנס משמואל לשאול - They go from leader to leader, from Shmuel to Shaul. Meaning that through the appointment of Shaul, the reins were passed and Shmuel lost his status of king which was effectively transferred to Shaul. And that fits very well with our explanation.
Now we can understand the Medrash that says that the Malchus of Yehoshua was שאולה - borrowed. Meaning that he was only considered מלך because there was no full fledged מלך and this means to emphasize that his דין מלך wasn't inherent to him but rather a title accorded by the Torah in cases where there was no political leader. For this reason the pasuk says in Divrei Hayomim ויורישו את ההגראים - they defeated the Hagraim, in the context of calling Yehoshua a king whose מלכות was borrowed. This war took place on the east of the Jordan and it was thus not a מלחמת מצוה but a מלחמת רשות. And the chidush of the pasuk is that even though the מלכות was only שאולה בידו - borrowed by Yehoshua, a "pseudo-malchus", if you will [and even if you won't], Yehoshua nevertheless waged this war.
Our thesis is really encapsulated by the Ran in his Drashos [דרוש י"א] who says that only when there is no king then the שופט acts as both שופט and מלך. And he concludes by quoting the pasuk about Yehoshua כל אשר ימרה את פיך - Anyone who defies your word [will be executed], which proves that the Yehoshua had the authority of a king even though he wasn't actually a king and Chazal expounded the pasuk ויהי בישורון מלך as referring to Moshe. And just about exactly the same idea was expressed by the Abarbanel in his preface to Sefer Shoftim. So we see the unique status of a שופט as a quasi-king empowered by the Torah but not a king intrinsically. And that was the nature of Yehoshua and Moshe's מלכות. And when there is another king, they lose their status as kings. But we must say that the Nasi and Resh Galusa are different because Rebbi [the Nasi] would have had the status as king had the Resh Galusa not been ABOVE him [as we saw earlier from the gemara].
OHHHHHH is there a lot more to say. Stay tuned. BLI NEDER!!
[עפ"י ס' באר מרים פ"א ה"ג]
[עפ"י ס' באר מרים פ"א ה"ג]