idea pos TL
Battle of Bull Run- Lincoln was pushing for the Army of the Potomac to do something. They moved south Lots of Washinton Bigwigs went along to watch the CS get it's A** kicked. The CS won and the Bigwigs fleed back to DC in Panic. The CS wasn't in shape to prusue.
POD. The A of P waits several more Weeks. let say one month
Jackson has arrived and reported to Lee. Lee has several more weeks to get to know his officers and prepare the Troops.
Bull Run happens with quicker CS victory. Stuarts Calvery prusues. Several leaders of Congress Captured. A day later the CS Army engages the AoP outside Arlington, and Captures DC. With CS Soldiers sitting in the Galleries the Congress passes a bill calling for Regoniziation of the CSA, and the removal of Congress to Philidelphia. Several week later the European Countries regonize the CS with GB hosting the peace conference.
With the Withdraw of the Agucultural South. the US reinsitutes the US Bank and focuses on Industrialization. Due to this increased focus by 1910, the US [dispite the loss of all territory south of the Mason-Dixon -Ohio river-Red River -line, is equal to to OTL in industrail might. Of course it's not quite the Agucultral giant. But with Friendly relations with it's Southern and Northern Neighbors, allow it to import and transshipp agucultrial products along with it's Industrial Shippments.