We have discuss Grant's raise to become Commander of all the armies before. I will try to review it for you. After his victories at Vicksburg and Chattanooga, Grant was the most popular soul in the land...His name was being used in some circles as to run for President.
Washburne and other approached Lincoln about revising Lt. Gen. position and promoting Grant to Lt. General. Lincoln was open to the idea but he had some concerns. He wanted to know if Grant had any desire to be President and to see if he was a Democrat or Republican....He truly wanted to know if Grant was a political threat or not.
Lincoln and Grant shared a mutual friend(can't remember the name) and Lincoln sent this mutual friend to talk to Grant and find out what were Grant's desires...The friend came back and told Lincoln, Grant had no desire to President and he was a Republican.
Grant by winning battles put him in position to achieve the honor as Lt. General but it was politics that got him the job....
Correlation does not imply causation. Whoever leads the victorious Union armies was practically assured of gaining such rewards. Similarly, I expect an NCAA men's basketball team to visit the White House in the near future. However, at this moment we do not know who (go Heels) it will be.
It may have been politics that landed Grant the LtGen job, but it wasn't *Grant's* politics...