Why was Yom Ha-Atzmaut established on the Fifth of Iyar?

[This year Yom Ha-Atzmaut was postponed until 6 Iyar]

There are those who ask why Yom Ha-Atzmaut was established on the 5th of Iyar in particular, since on that day no miracle occurred. The Jewish State was declared, and with it a life-threatening situation began (Chanukah and Purim were established on the day after the "war" ended). Our Rabbi, Rav Tzvi Yehudah Ha-Cohain Kook, explained that the courage to declare the State is the miracle of miracles, the soul and root of all of the miracles and wonders (Le-Netivot Yisrael vol. 1, p. 179). The Talmud discusses a shepherd who abandoned his flock, leaving it prey to either a wolf or a lion to come and tearit to pieces. The Rabbis established that his responsibility for the slaughter depends on whether or not he would have been able to save the animals. If he would not have been able to overcome the attacking animal, he is exempt from all payment. The Talmud asks: Why is this so? Perhaps it would have happened as for David: "Your servant slew both the lion and the bear" (Shmuel 1 17:36)? Perhaps a minor miracle would have occurred (Baba Metzia 106a)? The Tosafot describe the miracle: "A spirit of courage and the knowledge to wage war" (Tosafot ibid.). So too in the matter of the declaration of the State: "The awakening, the exerting of effort, the philosophizing and the strengthening for the drive to rescue and revive [the Nation]," is a miracle from the Heavens, "with a supreme and inner stimulus of power." The fact that the Nation of Israel was filled with the spirit to fight and the knowledge to wage war is the foundation of all miracles (Le-Netivot Yisrael ibid.). From this act flowed all of the miracles which led to establishment and strengthening of the State of Israel.