The border states were important as a buffer for the union from the confederacy. why was it important that maryland stay in the control of the union? because it was the first state in the union and had patriotic connections for many citizens because the nation's capital in washington dc would have been surrounded by confederate states if maryland had left the union because the union would have lost access to the south for offensive attacks because the number of union and confederate states needed to stay equal for balance of power in congress