The authors of "The Late Convention of Colored Men" believed the federal government had to protect the newly freed slaves from white Southerners because they feared they would be put into a situation similar to, or worse than, slavery. They also feared retribution by white Southerners because of their support of the Union army during the Civil War.
The authors make a plea to the federal government for protection, and they bring forth the point that they were quick to provide assistance to the Union in many ways during the war. They make the argument that they answered the call when the federal government needed assistance, and now they are hoping the same will be provided to them. The authors also state that, in addition to providing them a military governor, giving African American men the power to vote would also provide protection.
The authors of "The Late Convention of Colored Men" did have a valid point, as the end of Reconstruction in the South brought about the introduction of poll taxes, literacy tests, sharecropping, black codes, and tenant farming, all of which were designed to limit the ability of African Americans to improve their social or economic standing.