President Abraham Lincoln considered it crucial to prevent Maryland from seceding from the Union primarily because _________.
President Abraham Lincoln considered it crucial to prevent Maryland from seceding from the Union primarily because it surrounded Washington, D.C., on three sides. If Maryland had seceded, the U.S. capital city would have been surrounded on all four sides by the Confederacy. That was clearly untenable.
Ofcourse, Maryland was also important just because of the fact that it had a relatively large population and would have added to the manpower and industrial capacity of the Confederacy. However, the most important reason why Maryland, in particular, was important was its geographical location.