g over a large tract of country must pivot either on a railroad or a river, it appears that from Washington as a base, a force advancing against Richmond by the overland route, and having at the same time to cover Washington, is restricted to two lines of manoeuvre: 1.
The line of the Orange and Alexandria Railroad; 2.
The line of the Fredericksburg and Richmond Railroad.
Each of these lines was repeatedly essayed during the Virginia campaigns— the former by Pope and Meade; the latter by Burnside and Hooker.
Touching the merits of these lines, experience confirmed what theory would have postulated: that the line of the Orange and Alexandria Railroad, though an eminently defensive line as regards Washington, is hardly aggressive; and beyond the Rapidan involves so many complex considerations that no commander was ever able, on this line, to push an advance south of that river.
The Fredericksburg route is an aggressive line as regards Richmond, though it is surrounded with many diff