Why does the Torah use the double expression "Som Tasim alecha Melech!"?
Torah Temimah (citing the Sifri): If the current king dies then appoint another one in his place.
What are the implications of "asher Yivchar Hashem Elokecha bo"?
Targum Yonasan: It implies that before choosing a king, one should consult Hashem (presumably by means of the Urim ve'Tumim).
Why does the Torah repeat the word "Tasim alecha Melech"?