Hello Roy, I would agree with you after the Battle of 1st Manassas may have been the best opportunity to occupy Washington, save old Jube's Raid in 64' of course. However a couple of issues were at hand. The Confederate government was in a war to protect their own territory and invading the North was not on their agenda at this particular time period. Both Lincoln and Davis were equal in many ways. If the Confederates were to have taken Washington, DC in late July or early August of 61' Lincoln and his cabinet would have set up shop in another northern city. The Confederacy did not have the manpower to occupy every northern city they took. President Lincoln would not have surrendered in my opinion.