"The success of those doctrines would also subvert the Federal Constitution, change the character of the Federal Government, and destroy our rights in respect to slavery"

This quote by John H. Reagan is describing the doctrines of secession and also retraction, which were prominent in the South throughout the mid-1800s. Reagan is alerting that if these doctrines were to be effective, it would certainly have a destructive impact on the Federal Constitution, the Federal Government, and the legal rights of the Southern states in regards to slavery. He is suggesting that if secession and also cancellation were to be successful, it would certainly result in the dissolution of the Union and also the destruction of the rights of the Southern states to have slaves. Reagan is alerting that these teachings can have a tragic result on the country and its people. He is advising care and restriction in the face of these doctrines, as their success might result in the damage of the Union as well as the civil liberties of the Southern states.