In 1862, the Army of the Potomac was a wreck after recieving defeat after defeat at the hands of the Army of Northern Virginia. At Fredericksburg, the new commander of the AoNV, Patrick Cleburne (as Robert E. Lee had retired days after Sharpsburg) disgraced Burnside and Union President's replacement, Kearny, wasn't much better seeing as he lost Dumfries, an easily winnable battle, and got the AotP isolated and almost destroyed in Virginia for a whole year. What happens if Kearny won at Dumfries? How would the War of Southern Independence go? What of the Confederate occupation in the far west (modern day states of Apache, Comanche, and Sequoyah) and in Missouri and Kentucky. How would France and Britain react?
What are both the long term and short term effects of this?