The Temple and political capitol of the unified kingdom were in Jerusalem within the boundaries of Judah. The other tribes thought Judah was getting too much of a good deal for itself and rejected the leadership of David's grandson Rehoboam. That was probably not a bad thing, because Rehoboam (king of Judah) was using the kingship for his personal satisfaction, not God's. Jehoboam (king of 10 northern tribes of Israel) tries to solidify his political position by directly attacking the legitimacy of Judah and of the Temple and therefore of God, Himself. Did we not learn our lessons about golden calves by now? That lure of political power and wealth must be overwhelming because not even the wise Solomon could resist the pagan pull of many wives and David murdered Uriah.
I think the big take-away of the Old Testament so far is that confidence or reliance in your own wealth, wisdom, or political/social power leads you away from God and into failure, both now and forever. Man is flawed and we should not put our faith in ourselves. Look at our world today and see how many people have put their faith in men or institutions of men. Some might call that original sin. I think a little more God in our world would help alot!