The Tribal Politics of Ancient Israel:
In the days of David and Saul Israel was divided. A united Israel was a mere dream and a hope.. After the death of Joshua the tribes of Israel had seldom acted in unity for any reason. Only very strong and able leadership was able to bring them together for any length of time, and then only in times of national crisis. In fact it was probably for this very reason that the elders of Israel came to Samuel asking for a king. (1 Samuel 12:12) They felt they needed a king to unite them in order to fight against Nahash, king of the Ammonites, who had besieged Jabesh Gilead in Gad. But it was a mistake. The tribes could not be united politically. Each tribe had its own loyalties.
In order to understand tribal politics you would have to be a member of a tribe yourself, or at least have lived in a tribal context. The loyalties of the people are usually local; regional at best. They have their own local heroes, and their own local ruling class of elders and chieftans. They are loyal first to their own families, villages and clans. Jealousy rages against any outsider who manages to achieve something of significance, or gain prominence, unless those outsiders are subservient to the advancement of that community - and it is understood that when they die their descendants will not rule. It follows that anyone coming from some other community with any conflicting interest would be regarded as an enemy. For these reasons the tribes of Israel were hopelessly divided by trade, by occupation, by geography, and by history. The tribes in the north had taken up agriculture while the tribe of Judah was still largely pastoral. People valued their tribal identity above any so called national interest. The tribes were made up of clans which were in turn made up of large extended families. These close knit families had a common history and felt a common destiny. They would stick together against everyone else. Furthermore there were ancient hostilities between the tribes of Israel. They had competing claims of leadership.
The tribe of Ephraim claimed the right to rule because - Joseph was the firstborn son of Jacob's first wife, Rachel. Yes, that's right. By law, Rachel was Jacob's first wife. She had been betrothed (legally married), to Jacob before Laban's deceit and trickery forced Jacob to marry Leah ahead of Rachel. Therefore the right of leadership legally belonged to Joseph. And in fact, in the land of Egypt, Joseph had ruled over his brothers. Joseph's firstborn son was Manasseh. But Jacob had given the firstborn status to Ephraim. (Genesis 48:14-20) Thus the tribe of Ephraim claimed the right to rule in Israel.
note: The firstborn son was given a double portion of his father's inheritance. So it was that Joseph received a double portion in Israel. Both of his sons, Ephraim and Manasseh, received tribal lands in Israel. But Manasseh received a double portion of land because that was his right as firstborn. Yet Ephraim retained the right to rule.
Judah claimed the right of rule because Jacob had blessed him with that right. Just before he died Jacob had blessed Judah saying, "Judah, you are he whom your brothers shall praise; Your hand shall be on the neck of your enemies; Your father's children shall bow down to you. Judah is a lion's whelp; From the prey, my son, you have gone up. He bows down, he lies down as a lion; And as a lion, who shall rouse him? The scepter shall not depart from Judah, Nor a lawgiver from between his feet Until Shiloh comes; And to Him shall be the obedience of the people." Genesis 49:8-10
So it was that Ephraim and Judah both claimed the right to rule over Israel. However, up until the time of David, the tribe of Judah had never even tried to exercise that right. Ephraim, on the other hand, had always been the leader. The tabernacle had been placed in Ephraim's tribal territory at Shiloh. When you look at the map of Israel's tribal lands, you will see that all the tribes north of Ephraim would be dominated by Ephraim's brother, Manasseh. All the tribes north of Ephraim would be loyal to Ephraim. Only the lands of Benjamin, Judah, and Simeon lay to the south.
When the elders of the tribes of Israel came to Samuel asking for a king, Samuel was faced with a dilemma wrapped up in a conundrum compounded by multiple difficulties. Exactly which tribe would be chosen? Which clan? Which house? Whom would all the tribes of Israel follow? Initially the problem was solved by selecting a man from the tribe of Benjamin. Samuel had prayed, and that had been God's choice. The tribal lands of Benjamin lay exactly between the tribal lands of Ephraim and Judah. (see note below) Benjamin was also the smallest tribe and therefore would not provoke any jealousy. (1 Samuel 9:21) Benjamin could only rule by commanding the loyalty of the other tribes. Moreover, whoever was chosen to be king would have to be a charismatic, warrior king. Israel was threatened by enemies on all sides. The king would have to be a mighty man of valor, and a leader who could command armies. Saul was chosen for those reasons, and Saul understood that. Benjamin was Joseph's younger brother. As such he was uncle to Ephraim and Manasseh. It would be easy to command the loyalties of those two very large and warlike tribes. The other tribes would be a bit more difficult.
note: A king from the tribe of Benjamin might have made some sense, Biblically speaking. For Moses had said, "The beloved of the LORD shall dwell in safety by Him, Who shelters him all the day long: And he shall dwell between His shoulders." Deuteronomy 33:12 Italics mine. The Hebrew term "shoulders" implies government. (see Isaiah 9:6) If Judah was one shoulder, and Ephraim the other, would that not imply that Benjamin could be the head? God Himself seemed to think so. He told Saul that if he had been obedient, his descendants would have ruled over Israel forever. (1 Samuel 13:13)
In spite of some grumbling ( 1 Samuel 10:27) the plan worked - at first. Saul knew that he had to command the loyalty of all the other tribes. Therefore he went immediately to the rescue of the tribe of Gad. When Nahash, king of the Ammonites, threatened Jabesh Gilead in the land of Gad, Saul mustered all of Israel and went to the rescue. After the defeat of the Ammonites, the people went to Gilgal to renew their covenant with God, and Saul was crowned as king over all of Israel. Forever afterwards the tribe of Gad was loyal to Saul. Saul made his headquarters in Gibeah of Benjamin. Then, for more than a year, the "nation" was happy.
But that time of happiness and joy was not to last. Saul made a very rebellious early "mistake." By acting contrary to God's commands he decided to replace God as Israel's true leader. Thus he showed that he was not willing to obey God completely at a critical time in Israel's history. The prophet Samuel, who had been judging Israel, was still alive. He had told Saul to wait for him at Gilgal. When Samuel came to Gilgal, he would inquire of the LORD concerning the forthcoming battle with the massed armies of the Philistines. But Saul did not wait. Instead, he offered burnt offerings and peace offerings himself - in the place of Samuel. It is evident that Saul did not repent of his disobedience. Not long afterwards he refused to kill the king of the Amalekites, and also kept some of the livestock contrary to God's direct command. So God rejected Saul from being king. A young man by the name of David - of the tribe of Judah - would be chosen instead.
Saul's other mistake was to challenge the Philistines so soon after becoming king. There was not a sword or a spear of iron to be found in Israel. In other words they were not prepared for war with the kings of the Philistines. Although Saul was able to muster an army, the men of Israel trembled and feared before the assembled hosts of Philistine might. Worse, a champion named Goliath came out to mock Israel. A young hero would arise from the tribe of Judah and win national acclaim, at the expense of Saul.
Eventually David succeeded (at least to some degree), where all others failed. He was able to command the loyalty of all the tribes. He built his capital at Jerusalem, exactly on the border between Judah and the northern tribes. He married Ahinoam, the Jezreelitess, who was probably from the tribe of Manasseh, a northern tribe. He fought all of Israel's enemies on all sides and defeated them. And he was always careful not to offend the elders of the clans of Israel. Solomon, his son, would take the same wise course of action. But Rehoboam, Solomon's son, would not. Because of Rehoboam's foolishness, the northern tribes rebelled. It is interesting to note that Jeroboam, the first king of Northern Israel, was from the tribe of Ephraim. (1 Kings 11:26)
Once the kingdoms of Israel and Judah were split apart from each other they made war against one another; each attempting to defeat the other in order to unite the kingdoms once again. Neither kingdom could defeat the other. Finally there was a marriage between the two kingdoms. Jehoshaphat, king of Judah made peace with Ahab's son, Ahaziah. (1 Kings 22:44) Apparently this peace treaty was sealed by the marriage of Jehoshaphat's son Jehoram (AKA Joram), to one of Ahab's daughters (2Kings 8:18), the wicked Athaliah (2 Kings 11:1) Thus the two kingdoms and their monarchies were united by marriage and the warfare between the two ended.
note: In those days it was usually the king of the weaker nation who married the daughter of the stronger one. Judah was weaker than Israel at that time.
Last, but not least, it must be noted that during the reign of Josiah as king of Judah, the northern kingdom of Israel was defeated and destroyed by the Assyrians. The Assyrians led great numbers of the people of Israel away into the captivity from which they never returned. HOWEVER, a great many of the people of Israel fled southward as refugees into the land of Judah. Archaeologists say the population of Judah was doubled at that time. Then, through intermarriage, the tribes were at last united. After their return from Babylon the people still remembered their genealogies and lineages. Even in New Testament times it was still possible to count people from the tribes of Levi, Asher, and Benjamin. It is likely that people from Zebulon, Naphtali, Issachar, Manasseh, Ephraim, Simeon, Reuben, and Gad could also be found among the people of Judah. (These tribes are listed in the book of Revelations.) Thus the nations of Israel and Judah were at last united and had become one stick in the hand of the LORD. (see Ezekiel 37:19 below)
Thus says the LORD God: "Surely I will take the stick of Joseph, which is in the hand of Ephraim, and the tribes of Israel, his companions; and I will join them with it, with the stick of Judah, and make them one stick, and they will be one in My hand." Ezekiel 37:19
And so it is today in the land of Israel. There is only one nation, and it is known as Israel.