The united nation of Israel lasted only about 90 years, under three kings: Saul, David, and Solomon.
After that, the northern tribes divorced the tribe of Judah. We could describe the parting as anything but a civil war. The wars came later. But when Solomon's son took the throne of Israel and threatened high taxes and more brutal repression, all the tribes that could leave did just that. All that King Rehoboam was left with was his own tribe of Judah; they couldn't go anywhere.
Mostly kings not interested in God
Most kings—north and south—didn’t measure up to God’s lowest bar of acceptance. No kings in the north made the cut. In the south, godly kings included Asa and Jehoshaphat in 1 Kings and Jotham, Hezekiah, and Josiah in 2 Kings.
Two of the worst were Ahab and his Queen Jezebel. Ahab’s death ends the book of 1 Kings. But Jezebel lives to die another day, as dog meat outside her Jezreel getaway palace (2 Kings 9). Instead of looking out the upstairs window at the chariot corps commander who had just assassinated her son, the king, she should have run home to Lebanon.
Israel’s gilded age
King David secured peace in the region by defeating neighboring armies. Solomon inherited that peace and power. And he expanded it by adding subordinate nations as far north as the Euphrates River, on Turkey’s southern border.
This was Israel’s golden age—40 years of peace and prosperity for everyone but those commoners Solomon drafted. He didn’t draft them for the army. He drafted them for building projects like hauling rocks and timber for his palace and for building cities to help fortify and defend the kingdom.
That’s what did in his son. People asked King Rehoboam for a breather—some relief from the forced labor and high taxes. He said, “You think my father was heavy-handed. Compared to my heavy hand, my father was a pinky finger” (1 Kings 12:10).