If you wish to know about the validity of the claims presented by Magness and Page, please feel free to resubmit your question.

Suggestion: "How committed was Lincoln to the idea of sending freed slaves back to Africa for colonization?"

In the body of your question, I would then mention the Magness and Page's book.

Alternatively, you could ask "How accurate are the claims advanced by Magness and Page regarding Lincoln's views concerning black colonization in Africa following Emancipation?"

However, as submitted, the question is nothing more than soapboxing/leading phrasing, and has been removed.