Lincoln appointed Johnson military governor of Tennessee in March 1862, when much of the eastern part of the state remained under the control of rebel forces. Although Johnson was initially reluctant to recruit former slaves for the Union army—believing that they should continue to perform menial tasks, thus allowing white men to fight—Lincoln was aware that Johnson had “at least thought of raising a negro military force.” In this letter, the president urges him to follow through, arguing that “the colored population is the great available and yet unavailed of, force for restoring the Union,” and predicts that “the bare sight of fifty thousand armed, and drilled black soldiers on the banks of the Mississippi, would end the rebellion at once.”