Although King David was idealized by later Israel the Bible does not portray him as an ideal character. He was sly, cunning, vengeful, prideful, selfish, lusty — pretty much the description of most kings. One very savvy political move he made was the establishment of Jerusalem as his capital. The king and his men set out for Jerusalem
against the Jebusites who inhabited the region. The city had never been part of the tribal structure of ancient Israel so by moving there David demonstrated his independence — that he was not simply leading the tribe of Judah as he had been for the previous seven years but was now overlord of all the tribes. Creating a more just society will take similar political savvy by Christians today.