Political Promises...

And Abner sent messengers to David on his behalf, saying, “To whom does the land belong? Make your covenant with me, and behold, my hand shall be with you to bring over all Israel to you.” And he said, “Good; I will make a covenant with you. But one thing I require of you; that is, you shall not see my face unless you first bring Michal, Saul's daughter, when you come to see my face.” Then David sent messengers to Ish-bosheth, Saul's son, saying, “Give me my wife Michal, for whom I paid the bridal price of a hundred foreskins of the Philistines.” And Ish-bosheth sent and took her from her husband Paltiel the son of Laish. But her husband went with her, weeping after her all the way to Bahurim. Then Abner said to him, “Go, return.” And he returned.
And Abner conferred with the elders of Israel, saying, “For some time past you have been seeking David as king over you. Now then bring it about, for the LORD has promised David, saying, ‘By the hand of my servant David I will save my people Israel from the hand of the Philistines, and from the hand of all their enemies.’” Abner also spoke to Benjamin. And then Abner went to tell David at Hebron all that Israel and the whole house of Benjamin thought good to do.
When Abner came with twenty men to David at Hebron, David made a feast for Abner and the men who were with him. And Abner said to David, “I will arise and go and will gather all Israel to my lord the king, that they may make a covenant with you, and that you may reign over all that your heart desires.” So David sent Abner away, and he went in peace.
(2 Samuel 3:12-21 ESV)
Abner had maneuvered for Ish-bosheth, son of Saul, to become king of Israel. It was not long until it was evident that he himself was the powerhouse of the king's court, but things were not going as he hoped.  So he turned to David, the opposition, to jump on board. He also worked hard to get everyone else to come along with him. He abandoned Saul's son, making big promises to David, which he seemed able to keep.  Yet the question much have crossed David's mind: "If he has back-stabbed him, what might he do to me?"  Another thought might be: "Am I really dependent on him to bring about what God has promised?"  It is good and necessary for leaders to have plans and promise to achieve them, but let us keep our heads as to if and how they will happen, and who we really trust.