Lincoln had a very significant reason for imposing martial law on the state of Maryland. When Virginia seceded from the Union, Maryland became a very important state for the Union. Since Washington, D.C. was composed of land donated by Virginia and Maryland, it was imperative that Maryland remain in the Union. If Maryland were to secede, Washington, D.C. would have been cut off from the Union. The capital of the United States would have been in another country! Thus, by imposing martial law, Lincoln was able to arrest those legislators who were going to vote for secession. As a result, Maryland didn’t secede and remained in the Union. Martial law was imposed to save the capital from being in enemy hands. It wasn’t the only time Lincoln did something questionable in order to save the country.