I saw somewhere recently that when Tzidkkiyahu was blinded, he was invalidated from hypothetically returning to rule over Judea as king, because he now had a halachic blemish (מום). Is this true, that someone with a blemish cannot be king?
The Rambam in Hilchot Melachim (chapter 1) lists a number of conditions to be a king (not to be a convert, a woman, a butcher, barber, bath-attendant or a tanner). Having no blemish is not such a condition.
In addition, the Tanakh (Shmuel II 14:25) mentions Absalom was without blemish. If this was a mandatory condition to being a king, it wouldn't need to be mentioned.
As such, it appears to me that someone with a blemish can be a king.