According to Thomas Cahill, The Gift of the Jews, in what ways did ancient Israel function as both monarchy and theocracy?
Cahill argues that democracy is among the many gifts we owe to the Jews. From the time of Moses until Samuel anointed Saul as monarch, the Israelites were ruled by priests and judges who communed directly with God. Unlike in neighboring countries, the Israelites had no king. Because they lacked a monarch to appoint a priestly class, the people chose the priests and judges. In fact, it was the people who prevailed upon Samuel, who saw the folly in it, to give them a king.
After Saul became king, Israel moved from being a democratic theocracy, or a state ruled by priests, to a monarchy, a state with a king in charge. As God had warned, monarchy had its problems, among them taxation, but God told Samuel to give the people what they wanted so they could see for themselves what it was like. Monarchy would remain the dominant form of government for a very long time and the old, more democratic ways in Israel would fade.
As Cahill puts it, "because power adheres to the powerful, confirmation by the people has [had] fallen into disuse." In other words, once you move from theocratic democracy to monarchy, it's hard to go back again.